The North Island is being battered by wind and rain overnight, with one Auckland driver having a lucky escape after a large pine tree came down on her car.
As much as 160 millimetres of rain is expected to fall tonight across the upper part of the North Island, while Civil Defence has activated its emergency operations centre in Coromandel.
The peninsula is bracing for winds of up to 120km/h and up to 50 millimetres of rainfall.
Civil Defence is warning people to get to higher ground ahead of the storms. Many campers in Thames have already evacuated the area in preparation.
The Fire Service says it has been getting a steady stream of weather related calls around the regions since mid-afternoon, including reports of lines down and roofs lifting.
MetService says there is still a lot more wild weather to come.
There's already been 50 to 70 millimetres of rain spreading from Kerikeri southwards to parts of Taranaki and eastwards to the Bay of Plenty and Gisborne ranges.
The video by Helen O'Connor showsthe storm hitting Waihi Beach.
MetService meteorologist Nick Zcher says the ranges in the Bay of Plenty, Gisborne and the Central Plateau have received the heaviest rainfall.
He says the winds had exceeded 166 miles per hour in Northland, with gusts spreading further south as the night progresses.
He says despite the storm being fast moving, it's still developing and will continue to get stronger until noon tomorrow.
Tree comes down on car
In Auckland, a woman has walked away shaken but unhurt after the wild weather caused a large tree to fall on her car in Otahuhu.
Images taken and posted online by the Counties Manukau Fire Area show the tree across the front bonnet with a branch smashing through the passenger side of the front windscreen.
The area around Avenue Road and Trenwith Street is closed while an aborists clears the tree.
In the Coromandel, Mayor Sandra Goudie says locals had been kept well informed.
She says there had already been some sandbagging in Whangamata and localised flooding.
Civil Defence co-ordinator Bill Hutchinson says they were keeping an eye on river levels in Kaitiaia.
He says high tide would come at about 10.30pm-11pm, and said there could be potential for surface flooding.
Civil Defence has activated its emergency operations centre for the Coromandel Peninsula.
Thames Valley Civil Defence controller Garry Towler says the weather was likely to bring slips, downed trees and flooding in low-lying areas.
"It's going to be a short, sharp and nasty storm and people need to be prepared."
Motorists are being urged not to travel at night and freedom campers have been asked to move away from low-lying coastal areas.
The Pinnacles Hut and Kauaeranga Valley have also been closed to campers.
At Te Puru Holiday Park 16 campers packed up yesterday to go home to avoid the floods and the Sol3 Mio concert In Whangamata tonight has been moved to tomorrow evening because of the threat of extreme weather.
Farmers in Bay of Plenty are being urged to move their stock to higher ground as heavy rain pelts the region.
The regional council says between 100 and 150 millimetres is forecast in some areas tonight, and farmers near the Rangitaiki River and other eastern bay rivers should move their stock before then.
The council is spilling water from the Matahina Dam to make way for the extra water but says the spill will not flood additional land, and there is no flood risk to Edgecumbe.