Marlborough prepares for worst as up to 400mm of rain expected

Marlborough's Emergency Management is preparing for the worst, after MetService upgraded a heavy rain warning to the highest level.

The warning is in place for Marlborough and Canterbury, between Ward and Hanmer Springs and southeast of the Awatere Valley, including the Kaikoura Range, from 8pm on Monday to 3am on Wednesday. Up to 400mm of rain is expected to fall.

Marlborough District Council's incident controller Matt Kerr said it was the first time the region had been subject to a red rain warning.

He urged residents along State Highway 1 and nearby communities to be extra vigilant.

"There is a high chance of swollen rivers, slips and impassable roads.

"There may also be power outages and a loss of communications resulting in isolated communities."

Kerr also urged people to avoid travelling on State Highway 1, and not to take unnecessary risks such as attempting to drive through floodwaters.

NZTA is warning the South Island to be prepared for more snow, heavy rain, or ice that could make driving treacherous.

There was a likelihood of further road closures, after snow closed State Highway 8 between Fairlie and Lake Pukaki overnight.

There was also a risk of ice build-up that people should be wary of, it said.

Roading crews would be laying grit and anti-ice agents on the highways to assist vehicle traction.