Wild weather in Auckland has cut power to thousands of Auckland homes as a major storm approaches the South Island.

Photo: Metservice

A Vector spokesperson said there were eight outages affecting areas in Oratia, Mount Albert, Titirangi, Green Bay, Otahuhu, and Otara, affecting thousands of properties.

She said crews were working to repair the faults and make the network safe again, and power would likely be switched back on overnight.

Police said trees and powerlines had fallen down in the Auckland area due to the heavy rain and strong winds.

Heavy rain is forecast in the north and west of the South Island on Sunday and warnings are in place for the ranges of Marlborough and Nelson, and Buller and Westland.

The Metservice said between 100mm to 180mm was likely, with 50mm to 80mm possible in lower lying areas.

A burst of heavy rain is also forecast for Mount Taranaki.

Warnings of damaging northerly gales are in place for Taranaki, Whanganui and Taihape with gusts up to 130km/h to 140km/h.

Winds of 120km/h are likely from Taranaki to Wellington and the Marlborough Sounds.

A Metservice warning said winds of that strength could cause damage to trees, powerlines and roofs and make driving dangerous.

The low followed another 'bomb' low earlier in the week which brought much rain to the West Coast, causing slips which isolated some areas and bringing heavy winds to Wellington.

Drivers urged to be cautious in wet conditions

Otago police are urging motorists travelling between Cromwell and Gibbston Valley to stay vigilant and alert, following two crashes on the Gibbston Highway this evening.

There were no injuries, but police said traffic in the area was heavy, and the roads were wet and slippery.

Police urged motorists to keep their speed down, drive to the conditions and follow cars at a reasonable distance.