Severe weather warnings have been lifted, after a blizzard trapped people on Mt Ruapehu and skiers triggered an avalanche near Wanaka.

Wintry weather has hit much of the country, with snow and sub-zero temperatures from South Otago up to Wanganui overnight.

Photo: 123RF

Severe weather warnings have now been lifted for many parts of the country, despite more snow expected to fall.

MetService said heavy snow in Taihape, Taumarunui, Fiordland and Southland has eased.

Strong wind warnings for Hawke's Bay south of Napier and the Tararua District have also been lifted.

While today's severe weather may have calmed, meteorologist Tom Adams said the worst could be yet to come.

"Typically the coldest temperatures come later in winter, New Zealand being a maritime country it's heavily dictated by sea surface temperatures so mid-winter's day is typically not the coldest part of winter.

"August is looking like it's definitely going to get a bit colder."

Snow trapped party hunkers down for the night

Four children and two adults are settling down for the night in a deer hut after snow trapped their car in remote bush in Kahurangi National Park.

The group called police around 10am today to say their car was stuck in a ditch near Cobb Valley Road in the national park, near the top of the South Island.

Police said the six were safe, and had some food and plenty of firewood to keep them going.

No rescue party will be sent out tonight but they will assess the situation in the morning.

Skiers trigger avalanche

About 30 people were trapped at Ruapehu ski field by a blizzard, which struck about 10am, Ruapehu Alpine Lifts marketing manager Anna McLaren said.

The ski field has been closed and all those who wanted to get off the mountain have now been evacuated.

Ms McLaren said the skiers were brought down in vans, with the last one leaving the ski field just after 3pm.

Looks like a chilly morning for these campers at Lake Rotoiti in the Nelson Lakes ^TA pic.twitter.com/O8VHzwP4j9 — MetService (@MetService) July 30, 2016

She said a few skiers have remained on the mountain, staying in lodge accommodation.

Meanwhile, a group of skiers triggered an avalanche at the Treble Cone ski field near Wanaka.

The four skiers were in an out of bounds area around midday, when they triggered the size two avalanche up to half a metre deep.

The skiers managed to get out safely, and the area was searched to ensure no one else was caught in the avalanche.

Police and rescue teams from Wanaka conducted a search this afternoon with two dogs and a helicopter.

Photo: NZTA

MetService said the town of Clinton, in south Otago, was worst-affected by snow today, with reports of 19cm of snow.

Temperatures dropped below zero in a number of places in the South Island overnight, including Christchurch, Timaru, Lake Pukaki and Wanaka.

MetService said the combination of cold temperatures, blasting southerly winds and recent snowfall made temperatures feel slightly colder than they actually were, but 2016 has been a relatively mild winter.

A slip has closed State Highway 6 between and Hawea and Makarora.

Weather cuts power in Auckland

In Auckland, more than 350 houses are still without power after heavy thunderstorms hit the region this morning.

Vector said it was working to restore power to more than 240 houses in Mangere, 120 houses throughout west Auckland and more than 10 in Whangaparaoa.