Heavy rain, which caused surface flooding on several highways yesterday, is expected to ease in the South Island this morning.
The upper North Island will largely escape the wild weather, but rain is expected around the middle of the day in Auckland.
NZTA is warning drivers in Wellington and Wairarapa to take care as trees and debris could fall on roads.
Mark Owen, of NZTA, said winds of this strength can blow vehicles around, especially on State Highway 2 over the Rimutaka Hill.
"Particularly through the cuttings where you get accentuated wind, there's a risk they could get blown off the road or at worse into the path of an oncoming vehicle."
Meanwhile, Wellington City Council is keeping a close eye on demolition sites across the city.
Trolley buses were stopped temporarily yesterday and all ferries out of the capital were cancelled last night. Strong winds knocked a traffic light over in the city centre and a power pole reportedly blew over.
The MetService has also issued a strong wind warning for the Selwyn area, in central Canterbury, forecasting northwest gales gusting to 150km/h in exposed places until mid-morning.
The Selwyn District Council fears a repeat of the September 2013 windstorm which caused $75 million damage nationwide, damaging farm equipment, buildings and forestry plantations. Some areas in Selwyn were without power for more than a week.
Council principal rural fire officer Douglas Marshall said people should avoid operating machinery, or anything that could start a fire and to make sure previously lit fires are fully extinguished.
"Strong winds along with hot weather will create an extreme fire risk and fires will be difficult to control due to the extreme winds," he told the star.kiwi website.
The National Institute of Water and Atmospheric Research said incredible rain totals were expected for the west of the South Island, including in the Southern Alps where almost half a metre of rain was forecast.
