Icy roads in Southland have undone several motorists today, with six cars coming off the road - and similar conditions expected tomorrow.
MetService has issued a heavy snow warning for Southland, southern Fiordland and Clutha in the South Island, and the Hawke's Bay Ranges and Central Plateau in the North Island.
Southland road policing manager Deon McNaught said the region's east was hardest hit by the freezing weather but thankfully none of this morning's crashes were serious.
"We sustained quite a substantial amount of snow, which froze at about 5am, so when motorists woke up and started using the roads things were quite treacherous. That's subsided now during the hotter part of the day and the traffic has resumed as normal."
He urged motorists to drive to the conditions when black ice was about.
"If you do hit a patch of ice, you are at the mercy of the laws of physics - and I can't stress enough [that] the slower you're going at the time will dictate the outcome at the end."
The New Zealand Transport Agency's journey manager for Southland and Otago, Graeme Hall, said similar conditions were likely to cause more chaos on the roads tomorrow.
"The roads will stay wet down there overnight and, with the predicted freezing conditions, it's going to be very icy tomorrow morning.
"And, for coastal, we're expecting snow flurries down to 200 metres, so parts of Dunedin and especially the northern motorway - we'll be keeping updates as far as the road conditions [go]."
Margaret Taylor's family farm near Mossburn in Southland was covered in snow but her dairy cows were still able to get to their feed - kale and swedes.
"Of course, unless you get a foot of snow - then swedes and turnips will be buried - but luckily we haven't had that. They're pretty good at knocking the snow off if it's less than that; they can bite their way through it pretty good."
With the only road into Milford Sound closed since Sunday, Ada Lee - a worker at Milford's Blue Duck Cafe - said she had been enjoying some quiet time with her workmates.
"We cook food together and watch TV and play video games. The latest report is the road could be opening tomorrow but it depends on the overnight weather."
At 5pm, SH94 from Te Anau to Milford Sound and SH93 from Mataura to Clinton remained closed due to snow, and caution was urged on several other state highways in the South Island.
Snow showers were expected on all of the South Island's alpine passes by this evening.
Cold weather expected to move north
The bitterly cold southerly was expected to head north today and tomorrow, bringing snow to the central North Island.
Snow and ice has been forecast for some parts of the Wellington region with temperatures below zero °C expected tonight.
Snow was expected on the Rimutaka Hill Road between Wellington and Wairarapa and some of the city's hill suburbs, such as Karori and Newlands, may also get a dusting.
An earlier heavy rain warning for the Whanganui district, which is still cleaning up after severe flooding three weeks ago, has been lifted, but drivers have still been asked to avoid roads prone to slips.
Yesterday, three people were hospitalised after a crash on a flood-affected road in the district.