Meteorologists are warning "the storm is still to come" as a polar blast brings snow, rain and winds to the country this morning.
A severe weather warning remains in place for heavy snow, rain and gales for most of the South Island and Wellington, while the rest of the country remains on alert.
A woman was rescued from her home at Sawyers Bay near Dunedin early this morning after a landslip trapped her inside, and some homes at Leeston, south of Christchurch, have experienced minor flooding.
"The most critical thing is the storm is still to come," MetService meteorologist Daniel Corbett said.
"It's a dog's dinner. If this was a basketball match we'd be about the first quarter."
The weather will continue to worsen throughout the day and be "quite ugly" by tonight, Mr Corbett said.
Fire Service southern communications shift manager Riwai Grace said some people were waking this morning to minor flooding in their homes at Leeston. "I'm sure it's going to be the start of things to come," he said.
Flights were cancelled due to wild weather as the first snow fell in Southland yesterday afternoon, and MetService was warning much more was on its way for the south of the South Island and central North Island.
Heavy snow and severe gales are anticipated in many regions over the next two days, prompting a special weather advisory to be slapped on the whole country.
Electricity companies have warned of possible power cuts, emergency refuge centres have been set up, and shoppers are being urged to stock up but refrain from panic buying.
Police are warning motorists that insurers won't pay out claims to drivers who ignore road closure notices - and have warned anyone using roads that remain open to be wary of snow and black ice.
MetService is also warning severe gales will hammer parts of both islands, with Wellington, Auckland and Northland all expected to be blasted with icy winds.
The southern police district's acting top roading officer, Senior Sergeant Steve Larking, said invisible hazards may follow in the wake of snow.
"While snow is clearly visible, there may be large areas of black ice on the roads later that drivers cannot see - especially in rural and shaded areas."
Farmers should be well-prepared for the icy blast, with Federated Farmers saying hill and high country farmers had heeded early warnings to move stock. Lifestyle block owners have also been urged to look out for their animals' welfare.
Christchurch Civil Defence staff are on stand-by, having met emergency services and key agencies to prepare for the expected bad weather.
Bitterly cold southeasterlies will bring damaging gusts up to 150km/h for the South Island's West Coast, and 130km/h for exposed parts of Marlborough and Nelson.
The North Island should see snow falling to about 600 metres from late today until early Saturday, as south to southwest winds become very strong.
However, WeatherWatch head analyst Philip Duncan said flurries of snow may be seen at lower altitudes in Auckland, where there is a risk of hail and isolated thunder tomorrow.
"While the snow level will likely be 500 metres-plus, which is higher than the peaks in Auckland, downpours may be big enough to blow snow flurries down onto the tops of the Waitakeres, Hunuas and possibly Bombays," he said.
"However, the forecast for Auckland is very messy - so we'll need to update again in about 24 hours time."
- Kurt Bayer, Matthew Backhouse and Kieran Campbell of APNZ
