Wild Weather: Roads under water, Cook Strait storm warning, harbour ferries cancelled

Ferries have been cancelled and a storm warning is in force for the Cook Strait as the country braces for ferocious winds and heavy rain.

The first day of astronomical spring is off to a stormy start, with the MetService forecasting powerful and potentially destructive gales of up to 120km/h for eastern regions, including parts of Canterbury.

Nearly the entire South Island and the lower North Island is under a swathe of strong wind and heavy rain warnings and watches for the coming 24 hours.

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.

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, with modelling today suggesting it may 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.

While parts of the country are being deluged in wet weather, Christchurch will reach a balmy 24C today.