Weather: Cold front about to slam into South Island

A cold front is about to slam into the South Island on Saturday afternoon and Sunday, battering it with strong northwesterly winds and heavy rain.

"If you're tramping, camping, or otherwise trying to enjoy the outdoors in the South Island this weekend, heads up for a round of strong winds later Saturday into Sunday!" NIWA warns.

MetService has issued a number of severe weather warnings in the South Island, as the front moving up the West Coast brings heavy rain to western areas and central and southern areas feel the brunt of northwesterly winds.

In the lower South Island, heavy rain warnings have been issued around the headwaters of Otago lakes and rivers, around the headwaters of Canterbury lakes and rivers from Rakaia River southwards and for Fiordland. Strong wind warnings have been issued around the Southern Lakes area and in Fiordland, Southland and Clutha.

In the central South Island, there are heavy rain warnings in place for Westland between Franz Josef Glacier and Otira, around the headwaters of Canterbury lakes and rivers from Rakaia River southwards, Westland from Franz Josef Glacier southwards and the headwaters of Otago lakes and rivers. Strong wind warnings are in place for the Canterbury high country from Rangitata River northwards and the Canterbury high country south of Rangitata River.

The New Zealand Transport Agency warns the severe weather means motorists are advised to check before they travel.

"With heavy rain and severe nor-west gales forecast for much of the South Island over the weekend, Waka Kotahi NZ Transport Agency is advising motorists to check weather and road conditions before travelling," it said in a statement.

"Following storms and slips in December, SH6 south of Hokitika through to the Haast Pass has had single lanes and traffic management in several places.

"SH6 between Harihari and Whataroa will close overnight, as a precaution, if sufficient rainfall is expected. Motorists should be prepared to delay travel or change their route if necessary."

The front will weaken as it approaches the lower North Island early Monday.