A cold front will move northwards over most of New Zealand on Tuesday, says MetService.

A strong west to northwest flow precedes the front and a strong cold southerly flow follows it.

There is low confidence that northwest rain associated with the front could reach warning criteria about the ranges of Westland and southern Buller on Tuesday.

There is also low confidence that west or northwest winds could reach severe gale about inland Canterbury and Marlborough on Tuesday morning, and about inland and Central Hawke's Bay, the Tararua District and Wairarapa Tuesday morning and afternoon.

Behind the front, there is low confidence that southerly winds could reach severe gale for a time about exposed parts of Wellington and Marlborough on Tuesday afternoon and evening.

"Also note, that as the front moves northwards over southern and central New Zealand on Tuesday, the combination of cold southerlies and rain could bring snow down to around 500-700 metres over parts of the southern and eastern South Island, with the potential to affect higher roads and high country farms," says a MetService spokesperson.

"Finally, a small but deep low may pass close to the Chatham Islands on Wednesday and/or Thursday, and there is low confidence that winds may reach severe gale (either northerly or southerly) at the Chathams as the low passes by."

Heavy rain for Mount Taranaki, the Tararua Range, southern Westland and Fiordland

A slow moving front over the lower and central North Island brings a period of heavy rain to western areas, with Heavy Rain Watches remaining in force for Mount Taranaki and the Tararua Range. Another front is front is forecast to move onto the South Island from the southwest later on Monday, preceded by a strong and moist northwest flow, with Heavy Rain Watches now in force for southern Westland and Fiordland.

People are advised to keep up to date with the latest forecasts in case any changes are made, or further areas are added.

Heavy Rain Watch
Area: Tararua Range
Valid: 2 hours from 9:00am Sun 26 Mar to 11:00am Sun 26 Mar
Forecast: A period of heavy rain. Rainfall amounts may approach warning criteria.

Area: Mount Taranaki
Valid: 6 hours from 9:00am Sun 26 Mar to 3:00pm Sun 26 Mar
Forecast: A period of heavy rain. Rainfall amounts may approach warning criteria.

Area: The ranges of Westland south of Whataroa
Valid: 9 hours from 10:00pm Mon 27 Mar to 7:00am Tue 28 Mar
Forecast: A period of heavy rain. Rainfall amounts may approach warning criteria.

Area: Fiordland
Valid: 9 hours from 3:00pm Mon 27 Mar to 12:00am Tue 28 Mar
Forecast: A period of heavy rain. Rainfall amounts may approach warning criteria.

Watches no longer in Force
Strong Wind Watch lifted for Wairarapa including the Remutaka Summit: The threat of northwesterly winds reaching severe gale has passed and the Watch is now lifted.

Heavy Rain Watch lifted for the ranges of Buller and Westland about and north of Otira: The threat of rainfall amounts reaching warning criteria has passed and the Watch is now lifted.