Severe thunderstorms are possible overnight in Bay of Plenty and Rotorua, MetService warns, as the severe weather continues to lash the region.
Roads in Auckland are being monitored by police and fire service as water levels rise in Clevedon and Kawakawa.
Police said the Auckland Polo Club ground on Clevedon-Kawakawa Rd is flooded and the road was down to one lane.
It was likely to be fully closed soon due to heavy rain. Drivers should avoid the area if possible.
The Metservice has issued a severe thunderstorm watch, until 4pm today, for Auckland, with a front lying over the central Auckland area expected to bring periods of intense rain to Waiheke Island and eastern parts of Auckland.
Localised downpours of 20-30mm/hr may affect Waiheke Island and parts of Auckland east and south of the CBD during this time.
Rainfall of this intensity can cause surface and/or flash flooding, especially about low-lying areas such as streams, rivers or narrow valleys, and may also lead to slips, Met Service said.
Driving conditions will also be extremely hazardous with surface flooding and poor visibility in heavy rain.
In Bay of Plenty and Rotorua, a front is expected to move slowly eastwards across Bay of Plenty this evening and overnight with widespread heavy rain and possible thunderstorms.
Heavy rain was also drenching the Waikato region.
The thunderstorms are most likely about central and eastern parts of Bay of Plenty/Rotorua (mainly from Tauranga and Rotorua cities eastwards) after about 6pm, when a few may severe producing localised downpours of 25 to 35mm/hr.
The NZ Transport Agency said many Northland roads remain closed or with limited access following last night's devastating downpour.
Heavy rain has washed away a 10 metre-long section of State Highway 1 just south of Kawakawa in Northland, closing the road in both directions.
NZ Transport Agency Regional Journey Manager, Jacqui Hori-Hoult said the washout was still moving, and while the agency was doing its best to find an alternative route, the extensive flooding in Northland was making it difficult.
"We would advise people not to travel unless it is absolutely necessary, and if they do have to be on the roads to take extreme care. This storm has led to a lot of flooding and damage across our region."
Apart from the SH1 washout near Kawakawa, several other sections of Northland's state highway network are also affected by the storm:
- SH1, Kawakawa to Ohaewai: highway closed by floods; no suitable detour available
- SH1, north of Moerewa: flooding; caution needed
- SH10, Puketotara Road to Waipapa Road: flooding; highway narrowed to 1 lane
- SH10, near Kaeo: highway closed by floods; no suitable detour available
- SH11, Kawakawa to Paihia highway closed by floods at Lemons Hill
- SH12, near Kaikohe: highway closed by floods at Taheke; no suitable detour available
- SH12, north of Dargaville: highway closed by floods at Rotu Culvert; no suitable detour available
- SH11 Paihia to Kawakawa is closed due to flooding at Lemon's Hill and motorists are advised to avoid the area if possible.
- SH12 Kaikohe to Dargaville is closed west of Kaikohe at Taheke due to flooding and there is no suitable detour. SH10 is closed near Kaeo due to flooding and there is no suitable detour.
Care is also need on SH1 through the Dome Valley between Warkworth and Wellsford north of Auckland because of storm damage to the highway.
Hori-Hoult said people should drive to the conditions: lower their speed, increase their following distances, and use their headlights.
Northland police advised motorists travelling south through Morewa that water levels at the bottom of Turntable Hill, north of the township, were over half a metre deep.
Only trucks and large four wheel drive cars were able to get through.
While there was good signage south of the flooding, there was none to the north, police said. Contractors were in place to warn traffic.
Police said all non-essential travel should be delayed.
Graeme MacDonald, from the Northland Civil Defence Emergency Management (CDEM) Group, said up to 128mm of rain had fallen in the upper Waitangi catchment between 3pm yesterday and 6am today. Rainfall intensities of up to 36mm an hour were recorded in the upper hills at Towai.
The bad weather had now moved away from Northland which is expected to get some respite today and tomorrow. However, storm-filled rivers were expected to remain in flood this weekend before water can finally drain away. Parts of the region had received "huge amounts of rain" between 8am Tuesday and 6am today, with up to 524mm falling at Puhipuhi and 475.5mm in the upper Waitangi catchment.
MacDonald said officials began heading out to assess the situation at first light today with issues including significant flooding at Moerewa, Kawakawa and multiple flooding-related road closures, including on parts of the State Highway network.
All 2000 Auckland customers who had power knocked out overnight have had electricity restored Vector said while Top Energy crew were working hard to restore another 1200 residents in the Far North.
It hoped to have the number of properties without power "in the low hundreds."
Chief executive Russell Shaw urged anyone needing shelter, heating, food or water to contact the Far North District Council.
People shouldn't get too optimistic despite improved conditions in the north, he said.
"It doesn't matter how sunny it is. If we can't get to where the lines need fixing those homes and communities will remain without power. I want them to know, though, that we're making every effort to reach them.
"Our crews are taking it as a personal challenge."
Vector said conditions had eased across Auckland City but there was outages in Kaukapakapa affecting 190 customers due to trees on lines.
Spokeswoman Sandy Hodge urged people to log any faults in the system.
Northpower said 570 of its customers were without power this morning, 299 on the high voltage network and the others on low voltage lines.
Just after 5am a tree took out lines at Hukerenui, cutting power to 43 people. Northpower arborists and lines crews are working to restore power.
At Pukehuia, in the Kaipara District, 160 people were without power and lines crews are unable to access the area due to extensive flooding.
An aerial survey will be underway shortly and lines crews will then look to access the area by jetski and boat.
At Parua Bay, 28 customers remain without power and a helicopter is required to airlift a pole into rugged terrain. It is hoped that will be done today, along with another helicopter job in the Brynderwyns, a Northpower statement said.
Northpower also reported new feeder faults affecting areas near Dargaville and Hukerenui.
MacDonald said among key tasks today would be to assess welfare needs, particularly for those in isolated spots or who had been without power for several days, as well as checking electricity, roading and other infrastructural damage.
Some Northland residents fled their homes last night as the looming storm threatened to cause further havoc.
Northland Civil Defence said several residents in Moerewa had left of their own accord.
Emergency crews were providing assistance through the night and urged anyone seeking shelter or assistance to contact their local district council - FNDC 0800 920 029 or in the case of an emergency call 111.