Wild winds are lashing the capital and won't ease until tonight.
Wind gusts of 140 km/h have been recorded in the Wellington region, and things will continue to pick up until lunchtime MetService meteorologist Tom Adams said.
Mr Adams said winds were forecast to reach gale-force with gusts reaching 140 km/h in the city before lunch-time.
The mean speed for winds recorded at the Rimutaka Hill summit this morning was 110 km/h and gusts of 140 km/h had been recorded.
In Kelburn, closer to the city, a gust of 130 km/h had been recorded and at Mount Kaukau a gust of 133 km/h was recorded.
"We are in the thick of things," Mr Adams said.
"It could possibly pick up slightly more, but it's just about maxing out."
The winds would hit maximum intensity before lunch-time, Mr Adams said.
MetService issued a severe wind warning was issued for the capital. Trees, powerlines and unsecured structures would be at risk of being toppled and blown away and driving conditions would become hazardous for high-sided vehicles and motorcycles.
Heavy rain was forecast for Westland, Buller, and Mt Taranaki.
Wellington City Council received calls before noon about trees coming down or needing to be secured in Cockayne Rd in Ngaio, Johnsonville's Ohariu Rd, and Chamberlain Rd, Karori.
A city council spokesman said crews were being sent to fix or investigate the trees.
A severe weather watch was in place for Auckland with a chance of a short burst of heavy rain as the front bringing the heavy rain stalls around the Bay of Plenty region.
If the rain reaches Auckland it would be heavy around the evening.
The warmer temperatures experienced yesterday will stick around today, with Auckland reaching a high of 18C.
The weather was forecast to get interesting as the week developed with two systems moving over the country.
Mr Adams said a system of warm air and rain was moving across the North Island tomorrow and Thursday bringing rain to most parts of the North Island.
Later in the week a system of cold Antarctic air would move up to the South Island, he said.
"There's already good talk of Southland getting some heavy snow."
Where and when the snow would arrive was not yet established, Mr Adams said.
How will it affect transport?
The New Zealand Transport Agency said motorists in and around the capital should take extra care on the roads, watch following distances, and switch their headlights on.
Metlink Wellington said a harbour ferry sailing from Queens Wharf scheduled for 10am was cancelled. A 10.30am sailing from Days Bay was also cancelled due to rough weather.
One Air New Zealand flight from Dunedin due to leave at 10:50 and arrive at 11.25am was cancelled.
A member of the airport's operations team said it was otherwise business as usual at the airport.
KiwiRail and InterIslander ferry services were not affected this morning, a spokesman said at 11.20am.
Wellington Electricity said it also had no dramas with its network despite winds hitting up to 140km/h.