Tornado hits New Zealand
© Sam WanrooyA tornado struck at Ross, south of Hokitika.
The Haast Pass road is closed tonight by fallen trees as wild weather, including heavy rain and tornadoes, lashes parts of the South Island.

The New Zealand Transport Agency says it'll give an update about the Haast Pass by 10am tomorrow.

The Arthurs Pass road, State Highway 73, has reopened but care is needed after it was closed by extreme winds between Springfield and Arthurs Pass this afternoon which saw a trailer tip over.

A tornado hit Rutherglen about 10 kilometres south of Greymouth on the West Coast and another was reported at Ross, south of Hokitika, both whipped up by thunderstorms.

West Coast Civil Defence says there've been more thunderstorms in the region tonight but the worst conditions are high winds and heavy rain.

Spokesman Chris Raine told ONE News mid-evening the main front had still not arrived and there's a risk of stronger winds overnight, more thunderstorns and a small coastal tornado.

"But we won't be able to see funnel clouds in the night time so all we're going to hear is noise," he said.

Civil Defence staff will head out in the morning to check for any damage form the tornadoes.

Earlier a campervan tipped on its side in high winds on the Geraldine-Fairlie Highway, State Highway 79, in South Canterbury. No-one was injured.

Police are warning people to take care on the roads, as high winds have contributed to a number of crashes.

Severe flooding struck parts of Otago this afternoon as a severe weather system makes its way across the lower part of the country.

MetService has issued a severe weather warning, which includes heavy rain for parts of the South Island, Southern Alps and Tararua Range.

Three flights have already been cancelled at Dunedin Airport due to wild weather.

High winds are also expected tonight through to tomorrow morning in Canterbury, Marlborough, Wellington, Wairarapa and Hawke's Bay south of Hastings.

Up to 180mm of rain is expected in the ranges of Westland, where considerable rain has already fallen.

The front is due to move northwards and spread across the North Island on Friday.