There had been extensive reports of damage in the capital, but so far most of it minor.
Most significantly, a section of ceiling has collapsed on the third floor of the community health building at Hutt Hospital. Four staff members were evacuated.
Police spokesman Inspector Marty Parker said buildings in the city were being evacuated after structural damage was discovered.
A building on Featherston St was evacuated, as was the Mercure Hotel at the southern end of Willis St.
"The Mercure Hotel is being evacuated. Apparently they've suffered structural damage. They're evacuating that and a couple of surrounding buildings, as a precautionary measure."
Road blocks were in place around the Mercure, he said.
Heavy commuter chaos was also predicted for Wellington tomorrow morning. All train services were cancelled without any buses to replace them.
KiwiRail spokeswoman Sophie Lee said there had been no reports of damage to the tracks this evening. But because much of the assessment was done after dark, the call had been made to do a more thorough check in the morning, she said.
''Given the seriousness of the aftershocks and the fact that (the inspection) is taking a lot of time, we've decided to take every precaution.''
No buses were available on such short notice so rail commuters would need to make alternative arrangements, she said.
KiwiRail was hopeful of having at least some services back up and running by midday on Monday.
Land near the Wellington waterfront had also subsided into the sea.
Wellington Maritime Police senior launch master Barry Hart said a piece of previously reclaimed land along the industrial part of the waterfront had subsided into the sea, taking with it at least one shipping container.
"The land has actually subsided at least a couple of metres... into the sea. One shipping container has gone into the water."
He said the nearby container cranes were still standing and appeared not to have sustained damage. The ferry terminals also appeared to have survived unscathed, he said.
Victoria University geophysics professor Euan Smith said much of Wellington's city centre was reclaimed land which meant it was not as stable as other areas.
"Where rubble has come down in Featherston St, there was no land there before the 1855 earthquake in Wellington.
"Reclaimed land shakes more easily and is not as strong as hard ground. From Lambton Quay and towards the harbour is also reclaimed land, and these areas will shake much more strongly than other areas."
The Hutt Valley was similarly on softer ground.
"If this evening's was the first then I would say we could expect them to decay in the usual way, but given we had the earlier ones we should still be anticipating that there could be quite large earthquakes for the next few days."
Wellington mayor Celia Wade-Brown cut short her visit to Hamilton, making a late night dash back to the capital to oversee the earthquake recovery.
Wade-Brown was at Claudelands Events Centre for the Local Government Conference when the earthquake hit at 5:09pm.
She was being driven back to Wellington overnight and keeping in regular contact with officials in the city.
Her main message to Wellington residents was to be prepared for the big one.
''For me it's a really big reminder that everyone needs to be prepared, needs to talk to their neighbours, need to know that your family knows 'drop, cover, hold' and what plans are to get home and also that this is a time to charge your phones, check your batteries for your radio and so on,'' she said.
Adding to confusion back in the capital, the council emergency call centre had been shut down due to council buildings being unsafe.
The phone lines were being diverted and a temporary space was being found to move staff to. Deputy mayor Ian McKinnon said safety and security was paramount.
Victoria University tweeted that it would be closed tomorrow as a precaution following the shakes.
Wellington had received offers of help from neighbouring councils.
Porirua mayor Nick Leggett said he had talked with Wellington mayor Celia Wade-Brown and Greater Wellington Regional Council chairwoman Fran Wilde, and had offered resources to them if needed.
Porirua was "shaken", he said, and there had been some reports of damage, but most of it was people feeling uncertain.
"We're asking people to check on their neighbours, check on the elderly, make sure everyone's ok."
A spokesman from police said while there were lots of reports of broken windows and power lines down around Wellington, there were no reports of deaths or major property damage.
A fire service spokeswoman said people had to be rescued from lifts in Molesworth and Brandon Sts in Wellington city.
She said the fire service was still getting through a backlog of jobs. There remained a lot of alarms activated in the city, but those jobs were not a priority, she said. The alarms were activated by moving objects during the shake.
Fire crews were also draining a large amount of water which had poured from damaged pipes, near Brandon Street.
About 20 people had been evacuated from the Brandon Village accommodation in Brandon St in Wellington's CBD and told to find alternative accommodation for the night.
Electricity lines were down in Upper Fitzherbert Rd in Wainuiomata, a Wellington Electricity spokesman said. A line team was on scene and 442 customers were affected, he said.
Power to the remainder of the 3500 customers affected immediately after the quake had been restored.
A Victoria University spokeswoman said residential hostels suffered some minor damage. Weir House had broken windows and a ceiling panel fell down at a Willis St hostel.
A Wellington Airport spokeswoman said flights were diverted away from the capital between 6pm and 6.40pm because of fears the airport's navigational aid equipment had been knocked out.
Three flights were diverted to Palmerston North and another to Blenheim in the interim.
A flight from Auckland to Wellington was cancelled and 10 more were delayed.
Planes were able to land in Wellington after 6.40pm by using alternative navigational equipment, the spokeswoman said. Airport staff would continue to examine its equipment throughout the night.
The runway was assessed between 5.30pm and 6pm and no damage was found.
The Wellington suburb of Karori lost power when the big quake struck, it was restored about 5.45pm.
About 1000 customers remained without power in Wainuiomata.
Residents who rushed to the supermarkets for batteries and candles - in particular - were met with doors barricaded by shopping trolleys, and staff who said they were closed.
A worker at Karori Countdown said it was too dangerous to send staff into the shop, as a great deal of produce had fallen.
She had already fallen over once, she said.
People queued outside the door offering to pay whatever they had to produce, as it was not possible to get change.
The owner of the budget store in Karori Mall was offering to give his candles away, as a community service. He led grateful customers through the store by torchlight.
Wellington supermarkets were reporting panic buying as customers stocked up on emergency supplies like bottled water and canned food.
Karori New World was inundated once power was restored, with queues of panic buyers filling the aisles, while Countdown Karori remained closed.
Since the quake, senior supervisor Russell Gardner said he had noticed more customers coming in to buy specific items.
''There are quite a few coming in to stock up on things like bottled water - and a few worried faces too.''
Gardner said the introduction of special earthquake approved shelving in the supermarket a few months ago was clearly a good idea.
''It could have been a lot worse,'' he said, ''I think we have got off pretty lightly.''
Builder Kyle Woods was returning to his car from church when the quake struck. Large chunks of concrete fell from three or four stories, scattering around him.
The biggest chunk was about the size of his SUV car wheel, if not bigger.
''It all just came tumbling down, it was quite loud.''
Wellington resident Mike Gilbert was in the Embassy theatre when the 6.5 earthquake struck.
"We all crouched under the seats as the first quake hit. Lots of people headed for the exits but I thought, would it be any safer in the foyer? About half the audience left and didn't come back.
"It was pretty nerve wracking being under such a huge plaster ceiling but there wasn't any damage I could see."
One person had been injured and a lane closure was causing traffic delays.
Officials had confirmed one person was taken to Wellington Hospital with minor to moderate injuries. SH1 was reduced to one lane southbound while emergency services attended, causing minor delays.
Kapiti fire services responded to a rash of callouts, mainly to minor damage such as water pipes bursting.
Products fell off the shelves at Paraparaumu Pak 'N Save and people rushed out of the building.
Around the same time as the earthquake there was a minor car collision on State Highway 1 at the intersection with Kapiti Rd, which caused minor delays as emergency services attended.
Kapiti fire services responded to a rash of callouts, mainly to minor damage such as water pipes bursting.
At Harvey Norman Coastlands, a small portion of an interior suspended ceiling gave way.
About 15 minutes after the quake, there was a two-car crash at the corner of State Highway 1 and Kapiti Rd.
The Seymour Square memorial clock in central Blenheim stopped at the time of the quake.
A Blenheim police spokesman said there had been reports of power outages throughout the Marlborough region including Blenheim, Seddon and "many outer suburbs".
He was unaware of any damage to buildings or infrastructure, except burst water pipes, and said no injuries had been reported to police.
"The phone has been ringing non-stop but it's mainly about power outages and landslips on State Highway 1," he said.
There was a slip on Highway 1 south of Seddon, which was believed to be as a result of the quake.
Marlborough Roads general manager Frank Porter was not sure of the exact location. But a team had been sent out.
It was not yet known whether the highway would be closed.
Emergencies Services manager at the Council, John Foley, said power was out around the region, and Marlborough Lines were checking to see how long people would be without power.
Foley confirmed there were slips being investigated around Seddon.
He said there had been reports of water pipe damage and the emergency management team were trying to confirm that. There were no reports of injuries or building damage he was aware of.
He advised people to remain where they were, and to pull out their emergency kits.
The Warehouse Blenheim manager, Ian Daubney said glass had smashed all over the floor and a lot of stock had been damaged.
The store was evacuated and closed briefly while staff cleaned up the mess.
"It was huge,'' he said. "It shook our staff something wicked.''
The store had been re-opened so people could stock up on emergency items such as batteries and water, he said. Rarangi fire force controller and civil defence manager Steve Banks said Rarangi had lost power.
He had cordoned off the road heading over to Whites Bay because a few slips had come down on the road, he said.
Seddon man Murray Gray was finishing his pint at the Starborough Tavern when the 6.5 magnitude earthquake hit.
Bottles fell off shelves, smashed on the floor and the power went out, Gray said.
''Shit, she shook out here,'' he said. ''It was pretty terrifying.''
Gray decided it was time to get home but had a look through the bottle shop door first.
''There was crap all over the floor but I wasn't hanging around,'' he said.
Back at his house, all the pictures were off the walls and cupboards and drawers had opened.
His wall clock had stopped at 5.10pm.
''It's a bit of a mess but no structural damage,'' he said. ''We had a few empty shelves but nothing too serious. We've got a couple of candles going so she's all good.''
Rarangi resident Bev Doole said the Sunday evening earthquake was the biggest she had ever felt.
''We're ok, we have no power, but we're ok.''
Without power, they were heating soup on the wood burner, Doole said.
Lake Grassmere farmer Anna Booker was outside feeding the chickens when she saw a line of huge macrocarpa trees begin to sway.
"They were all shaking. I was just happy I was outside,'' she said.
Shelves had fallen down in the pantry and photo frames and pictures had come off the wall.
"It was way bigger than this morning's one.''
Grovetown resident Elizabeth Bell said power was out in Grovetown.
The earthquake there was ''huge'' with food falling down in her pantry, stuff falling over in the garage, and pictures falling off walls, she said.
Rapaura resident Sue Bell said the earthquake was very strong, with her house moving enormously. It frightened her grandchildren and it shook ornaments off their shelves. ''I grabbed the television with one hand and the side of the door frame with the other.''
The quake was felt in Palmerston North this evening, although early reports indicated no damage in the region.
Sarah Stevens was just outside of the city when the quake hit. Her and her family huddled in doorways for what seemed like "a good 20 seconds or so of quite violent shaking".
"We didn't feel any of the other earthquakes over the past couple of days but that one we certainly did. The floor felt like waves and the light fittings were all swinging around.
It was very frightening," Stevens said.
Aftershocks continued to rumble from the same area, and a 4.4 quake struck at 5.14pm, 15 kilometres north of Hunterville.
Palmerston North fire station had no reports of damage, and power was not lost to any part of Manawatu.
People took to social media to give their reactions to the quake.
Village Inn Kitchen tweeted, "Don't worry we are still pouring beer the fridge is fine and I hope everyone is ok."
Rapper PNC, who was in town for a gig at Mr Cue last night, said he also felt it.
The quake caused minor damage in Manawatu, prompted theatre evacuations and saw Wellington-bound planes to divert to Palmerston North.
Palmerston North fire service were not called out to any jobs as a result of the quake, and power was not cut off to any part of Manawatu.
There were various reports of stock falling off shelves in both New World and Countdown supermarkets in Feilding, along with various Palmerston North supermarkets, but staff said there had been no significant damage.
Theatre goers were evacuated from The Regent near the end of a production of The Gypsy Baron by Johann Strauss II.
Some flights were diverted from Wellington to Palmerston North Airport over fears navigational equipment at the capital's airport had been damaged during the shakes.
Fairfax employee Clive Lind was on a flight from Christchurch to Wellington which was in the air when the quakes hit.
''We got to about the Cook Straight and they said 'Oops, there's just been an earthquake and we can't land until they check things out'.''
The plane then circled above Wellington for some time before passengers were told they were diverting to Palmerston North, he said.
''The canteens [at Palmerston North Airport] have done marvellous business.''
Buses were taking passengers from Palmerston North to the capital.
People in Manawatu certainly felt the shake and took to the Manawatu Standard's Facebook page to share their experiences.
Rebecca-Kynan Bright said she felt it in Marton.
''Our fish tank was sloshing all over. Family ducking for cover.''
Gina-Marie Fanning said it felt strong in Palmerston North.
''It went on for so long that I went under the door for cover, but my 12-year-old son wouldn't get off the computer until I growled at him to get off.''
Kate Wilkie: ''That was pretty big the house shook sideways for ages! Stood in the doorway gonna have the torch next to bed tonight!''
Palmerston North MP Iain Lees-Galloway posted on his page that it was the biggest quake he had ever felt in Palmerston North. ''Look after each other.'
Calls came flooding in from concerned residents throughout the greater Waikato region who figured ''someone's been hit hard for us to feel it''.
Residents from Cambridge, Tamahere, Morrinsville, Te Awamutu and Ohinewai, north of Huntly called with their stories of the quake, which was mainly described as a gentle rocking motion that went on for around 45 seconds.
But the quake literally turned back time for Cambridge couple Margaret and Gary Hampson-Tindale who were stunned to hear the chimes of their mantelpiece lock after 13 years of silence. The pair, both aged 73, purchased the ''pendulum chiming clock'' prior to getting married more than 48 years ago.
''It has always gone like, well, clockwork,'' Mrs Hampson-Tindale said. But the retired farming couple couldn't find a suitable shelf for their clock when they moved to a home in Cambridge about 13 years ago.
''So Gary put the clock away and silenced the pendulum - we haven't heard it since.''
But that all changed about 5.10pm last night when the clock was jolted back into life by the forces of mother nature.
And right on queue, the chimes sounded again at 5.30pm as Hampson-Tindale shared her story.
''I think we might have to find a place for it again - I quite like hearing it after all these years.''