People are being urged to use common sense and listen to media reports on road conditions and closures if the forecast blizzard conditions and heavy snow eventuates in Otago this morning.
A severe weather warning issued by the MetService yesterday predicts heavy snow for Southland and Otago, mainly overnight.
Forecaster Andy Downes said a bitterly cold southwest flow over the South Island could bring snow to near sea level.
"Strong or even gale-force southwest winds about exposed coastal areas and the hills are likely to lead to blizzard conditions with heavy, drifting snow and very low wind-chill temperatures."
In Dunedin, snow showers were expected last night, with heavy snow predicted overnight.
In the 15 hours to 9am today, 10cm to 15cm of snow was likely about the hills above 200m, especially in South Otago and the Catlins, with 2cm to 5cm possible down to near sea level in Dunedin and in Invercargill.
The New Zealand Transport Agency yesterday warned of high winds on State Highway 1 from Milton to Balclutha and cautioned campervan drivers and those towing caravans to take extreme care until further notice.
Chains were to be carried on State Highway 94 between Te Anau and Milford Sound because of snow.
The principal of Balaclava School, Sally Direen, said a group of Dunedin hill suburb principals would make the decision this morning about a late start for or closure of the city's hill suburb schools.
Schools are advising parents through newsletters to listen to the radio if the weather looks doubtful in the mornings and not to drive if streets and roads were not safe.
Dunedin City Council roading maintenance engineer Peter Standring said roading contractors were put on "high alert" yesterday and would be making regular checks of the city's roads throughout last night.
"Our contractors will be out and doing their best to keep roads as clear as they can, but we will keep people as informed as we can."
If there was a heavy snowfall, people had to drive to the conditions.
Road closures would be well publicised, he said.
A MetService special advisory also predicted snow showers today for eastern Canterbury and the Kaikoura coast.
The cold spell was also expected to bring snow showers to the central North Island high country above 800m last night and then lower, to 200m-400m, today in the lower half of the island.
