Harbour ferries have been cancelled and a storm warning is in force for Cook Strait as the centre of the country braces for ferocious winds and heavy rain.
And forecasters are predicting more atrocious weather to hit the country this weekend, with one describing the approaching storm as a "weather bomb".
The first day of astronomical spring is off to a stormy start in central and southern New Zealand.
Nearly the entire South Island and lower North Island stretching as far as Taranaki is under a swathe of strong wind and heavy rain warnings and watches for the coming 24 hours.
MetService has forecast powerful and potentially destructive gales of up to 120km/h to pound eastern regions of both islands.
The capital continues to be lashed by strong winds after a wakeful night.
MetService forecaster Mmathapelo Makgabutlane said gusts as strong as 128km/h were recorded at Kelburn and 120km/h on the Remutaka Hill Rd, where a warning still remains in place for motorists.
Heavy overnight rain has deluged the West Coast, with the main highway linking Haast and Hokitika affected by surface flooding.
At this stage, State Highway 6 is not closed but the New Zealand Transport Agency is warning motorists to drive carefully in the terrible conditions.
Makgabutlane said 73.8mm had fallen in just 12 hours in Milford Sound since 9pm last night, while 50.4mm had fallen in Westport where it was still continuing to rain.
A storm warning is in force for Cook Strait, with winds around 100km/h expected to barrel through the channel this morning.
As conditions start to deteriorate in the capital, commuter ferries that shuttle workers across Wellington Harbour are running to a restricted timetable this morning as the weather sets in.
There are no sailings in or out of Seatoun this morning.
Neither Interislander or Bluebridge Cook Strait ferries have changed their timetable.
MetService has posted a storm warning for Cook Strait in its marine forecasts, saying those using the strait will encounter high seas and poor visibility as heavy rain lashes the centre of the country across the day.
A marine gale warning is also in force, with winds of more than 100km/h due to hit the stretch of sea connecting the South and North Islands this morning.
The country is in the grip of the first of two powerful storms to hit the country in the coming week.
A second nasty low-pressure system is expected to rapidly develop this Sunday and Monday. One forecaster's model suggested it might reach weather-bomb criteria.
Weatherwatch.co.nz warned the South Island could find itself in the grip of a second bout of bad weather including gales, snow and bitterly cold temperatures and more heavy rain for the West Coast.
MetService is also warning the front will bring heavy rain to the West Coast and snow to alpine regions before a cold southwest change on Sunday would see snow down to 400m in the far south.
The severe outlook also said severe northwest gales were likely to affect central New Zealand, particularly regions from Canterbury to Taranaki.
While parts of the country are being deluged in wet weather, Christchurch will reach a balmy 24C today.