Snow is expected to affect the central North Island high country above about 900 metres, MetService said.

Many South Island areas above about 200 metres are also likely to be affected by snow.

"This snow and cold temperatures are likely to bring stress to livestock and make driving conditions hazardous.

"Warning amounts of snow are generally considered unlikely, but there is low confidence that warning amounts may accumulate above about 600 metres in South Canterbury, south of the Rangitata River."

Strong southerlies are also expected to affect much of New Zealand.

"There is low confidence that southerly gales will be severe about Wellington and the Marlborough Sounds, and low confidence that severe southwest gales will affect Northland in the evening." 

On Wednesday, strong cold southerlies are expected to affect the country but the risk of severe weather is minimal.

A ridge of high pressure is forecast to affect the South Island while cold southerlies cover the North Island on Thursday. The risk of severe weather is minimal.

On Friday an area of high pressure is expected to be moving east on New Zealand. The risk of severe weather is minimal.