Weather: Major Antarctic blast heading to New Zealand

A "significant" polar blast is on its way to New Zealand - and an expert warns it could kill.

Weather Watch is urging farmers to be prepared for a late winter storm next week as the Antarctic southerly tears towards the lower South Island.

"This looks to be one of the more significant southerlies of 2018, at least for the lower part of New Zealand," says head forecaster Philip Duncan.

The "major Antarctic blast" could see very low level snow in Southland and Otago. Snow is quite possible in Queenstown, Wanaka, Lumsden and potentially Dunedin's hilltop suburbs.

There are fears the biting wind could be cold enough to kill livestock as spring lambing continues.

"Daytime highs will be miserable along with wintry, damp, southerlies," Mr Duncan says.

"Whether it's snow flurries or just wintry rain showers, the reality is that this will be a miserable week for livestock in the lower South Island - especially newborn lambs with daytime highs next Wednesday ranging from just 3degC to 9degC there".

Storms have already ravaged North Island farmers earlier this month, after significant rainfall and gale winds over a week from the start of September.

Senior Analyst with AgriHQ, Mel Croad, says some farmers she has spoken to say it is the worst they've seen in more than 20 years.

"It was a tough environment for newborn lambs, with prolonged cold and wet weather," she said.

She estimates the lamb losses could be more than 100,000, with many farms over Wairarapa and Hawkes Bay reporting losses of between 100 to 1000.