UPDATE 7.53AM: While parts of the North Island have already copped a drenching, forecasters warn we haven't seen the worst of the winds yet.
Coromandel, Auckland, Waitomo and the Bay of Plenty are likely to be hit by powerful winds of up to 120 kilometres an hour between 7 and 10 this morning.
Weatherwatch head forecaster Philip Duncan said the storm system will continue to gain power as it moves down the country.
"The worst of the wind, they're wrapped around the centreof the low, and because the low is still developing we're not likely to see the worst of those winds until the centre of the system comes up and landfall is likely to be somewhere around Taranaki and the rest of the western North Island."
There's more rain in store for much of the country today.
The top part of the rainband is now over Wellington but will move further south.
But MetService duty forecaster Sarah Haddon says the rain is wrapping back into the low over the North Island, and will continue to affect all of the North Island today.
She says in the Far North, showers are expected to ease away by afternoon - but for the rest of the North Island it won't let up until this evening or overnight.
Rain in the South Island will mainly affect Canterbury, Marlborough and Nelson.
As the low draws near parts of NZ still have strong winds & bouts of heavy rain forecast - see if ur area is under any Severe Watches/Warnings here https://t.co/qHyE5zhh6X. The hand drawn isobar chart shows where the strongest winds are atm - where the lines are most bunched ^AC pic.twitter.com/yIk4CMH1Om— MetService (@MetService) January 4, 2018
The wild weather has seen thousands without power across parts of the North Island.
More than 9000 properties in Whitianga were plunged into a black out just after 6.30 this morning, with power expected to be restored at around 9.30am.
Across Rotorua, Napier and Hastings power is cut to more than 2000 properties.
They include nearly 600 in Rotorua, nearly 400 in Napier, and just over 1100 in Hastings.
And there are widespread power outages in the Auckland region because of strong winds overnight.
They stretch from Mangawhai to Whitford, and include Waiheke Island.
@MetService Winds continue to increase this evening, with strongest gusts spreading south across Northland and northern Auckland. Wind gusts exceeding 110km/hr now stretch from Whangaparaoa to North Cape. ^NZ
— MetService (@MetService) January 4, 2018
However, the severe rainfall and gale force winds predicted have largely skirted around Bay of Plenty.
Much of the area was expected to see flooding and severe winds whipping through the region overnight.
Regional council flood manager Mark Townsend told Tim Dower the region was well prepared, with people battening down the hatches but they got off lightly.
The wild weather has prompted the closure of The Mount at Mount Maunganui, but that hasn't put off die-hard walkers.
Tauranga City Council closed the base track around the popular reserve at 7am for safety reasons, with huge swells expected.
But the track leading to the Mauao summit remains open, with locals still venturing up on their morning walks.
However, walkers say the base track was already dangerous this morning before it was closed, with huge waves.