MetService has issued a snowfall warning for the Desert Road - State Highway 1.

The warning is valid for 15 hours from 7am - 10pm Monday, August 19.

"Snow showers are expected above about 1000 metres from Monday morning through to Monday night, where 1 to 2 cm of snow may accumulate at times," says a MetService spokesperson.

On Tuesday, August 20, a ridge of high pressure is set to bring settled weather to much of the country, with minimal risk of severe weather.

This ridge of high pressure continues through Wednesday to bring settled weather to much of New Zealand.

"Severe weather is unlikely," says a MetService spokesperson.

On Thursday, a front, preceded by a strong and moist northerly flow, is expected to approach the South Island from the Tasman Sea.

"There is low confidence that this front will bring warning amounts of rain to Fiordland and Westland south of Haast," says a MetService spokesperson.

"There is also low confidence that north to northwest gales will become severe in exposed parts of Fiordland, western Southland, and Stewart Island."

On Friday, August 23, a front, preceded by a strong and moist northerly flow, is forecast to move northeastwards over the South Island and onto the southern North Island.

"There is moderate confidence that this front will bring warning amounts of rain to Fiordland and the Westland District, with significant spillover into the headwaters of the Otago and Canterbury lakes and rivers.

"Meanwhile, there is low confidence of warnable amounts of rain for the Grey and Buller Districts, also western Tasman, the Tararua Range and Taranaki Mounga.

"There is also low confidence that north to northwest gales will become severe in exposed parts of Stewart Island, western Southland, Fiordland, Queenstown Lakes District, the Canterbury High Country, and Wellington including the Remutaka Hill Road, with winds expected to ease following the passage of the front."