Severe weather on the way

File photo / APN

Thunderstorms, gales and flash flooding are on the way as severe weather gets set to lash the country, forecasters say.

The MetService has issued severe weather warnings today for Buller, Westland, Nelson, Marlborough, Fiordland, Canterbury, Otago and Southland.

A front over the Tasman Sea is set to hit the country, bringing rain to most places.

The MetService is warning heavy rain could cause streams and rivers to rise rapidly, with flash flooding possible.

Strong winds could bring down trees and power lines and make driving hazardous for motorcycles.

Thunderstorms were likely, with a high risk in northern Westland, Buller, Nelson and the Marlborough Sounds.

"Today's trough will spread the area of rain and thunder, currently across northern areas of the South Island, to many western parts of the North Island during the late afternoon [and] evening especially from Taranaki down to the Wellington region,'' MetService meteorologist Daniel Corbett said.

"This will just be a few showers by the time it reaches the eastern and northern areas later tonight.''

MetService's rain radar for Friday looks grim for much of the country.

Buller could expect the heaviest rain today with an expected 50mm to 70mm.

Auckland would see showers and "a rumble or two'' of thunder, but most of the more severe weather would be further south, he said.

A second front approaching the South Island on Thursday would be accompanied by gale-force northwesterlies and heavy rain - especially in Fiordland, Westland, Otago and Canterbury Headwaters.

Things wouldn't calm down until next week, Mr Corbett said.