"Our teams are clearing the snow and applying de-icing treatments, please take extra care," a message on the website stated.
The heavy dumping of snow also brought warnings for all the main passes, and the Dunedin to Waitati Highway.
Heavy snow warnings were also in place for parts of Otago and Southland, and there are watches from Hawke's Bay to Canterbury.
Tom Adams from MetService said it was "absolutely freezing" with visibility and icy roads causing hazards.
Parts of the South Island woke to snow this morning. Photo / MetserviceDrivers were warned to take extra care and farmers to check on livestock.
"There are a few roads closed so we would urge people to check the NZTA website before heading out," Adams said.
"Some of the roads have snow that has melted overnight and frozen so they are pretty icy."
MetService forecaster Lisa Murray said cold air was coming off the polar ice cap, turning rain to snow, especially at high levels in the south.
Arthurs Point residents woke up to a blanket of snow. Photo / Louise Scott, Otago Daily TimesShe said snow flurries or sleet could fall at low levels or sea level, but it wouldn't stay on the ground.
MetService expected a strong, cold southwesterly flow over southern New Zealand, with snow falling to low levels last night and this morning.
Heavy snow was expected above 400 metres in southern Otago and the Southland hills, and around 10 to 15cm was expected by 9am.
Snow on the hills in Hanmer. Photo / MetserviceThis is in addition to any snow that has already fallen.
Severe southwest gale warnings were issued for Clutha and Dunedin through to this evening.
