Wellington commuters will feel the effects of the earthquake well into Monday with all morning train services in the region cancelled.
KiwiRail 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
KiwiRail services from Otaki in the North Island to Kaikoura in the South Island had been suspended until further notice.
There could be some disruption to freight services between Picton and Kaikoura, while an inspection of the tracks, bridges and tunnels was done, the spokeswoman said.
Phone lines jammed in the top of the South Island and bottom of the North Island immediately after the large quake struck as people tried to call family and friends, a Telecom spokeswoman said.
Both the mobile network and the landline network were overloaded for 15 to 20 minutes.
''There was a spike in traffic straight after the quake hit, which is as we would expect - everyone getting on the phone to make sure their family is OK.
''To the best of our knowledge there's no network damage.''
People should send text messages, instead of calling, to ensure emergency calls can get through, the spokeswoman said.
Vodafone customers were also affected when nine mobile sites went down immediately after the large quake.
Sites in Marlborough were affected by power outages and two Wellington sites lost coverage, a spokeswoman said.
''Some customers may have had problems with calls and texts following the quake - issues compounded by overloading on the network, rather than damage.''
The network was now stable and all mobile cell sites had been restored.
''Our guys are just making sure now that staff are OK, buildings are OK and that the network is stable.''
Five 2degrees mobile sites were affected in Wellington and Marlborough due to power outages, a spokeswoman said.
These sites switched to back up battery power and continued to operate.
She said there was an increase in calls and texts but ''nothing that put any pressure on our network''.
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.
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.
A spokesman for the NZ Transport Agency said an initial damage report of state highways in the quake zone was done and no damage or blockages were found.
The agency would carry out more detailed inspections tomorrow, he said.