Several of the highways that have reopened have restrictions in place. For the latest highway conditions click here
The only highway still closed is SH94 from Te Anau to Milford Sound, the only one where an alternative route was not available, NZTA Otago-Southland Operations Manager Roger Bailey said.
"Although many highways are now back in action there are still a number of patches of snow and black ice. While our contractors are dealing with these as quickly as they can, motorists need to take extreme care and drive to the conditions."
Meanwhile, power has been restored to the last of the homes near Clinton that had faced another chilly night with power outages due to the snow.
PowerNet, which runs the electricity networks in Clutha and Southland, lost power last night after "snow loading" caused some power lines and poles to fall, PowerNet network maintenance manager Ian Robertson said.
He said the power to the 38 homes near the Clutha township had been restored shortly before 11.30 this morning, they had been without power since just after 8.30pm last night.
Earlier, Dunedin schools started late because of icy roads and emergency services attended more than a dozen crashes in and around the city, including one which has left a man in Dunedin Hospital with serious head injuries.
Acting Senior Sergeant Tania Baron said the man was cut out of his red BMW after losing control on black ice on Maclaggan St shortly before 4am.
The Serious Crash Unit is investigating.
That crash, and others in the CBD including York Pl, Stuart St and London St, served as a reminder for people to postpone essential travel due to the treacherous conditions, Snr Sgt Baron said.
Several crashes were also reported in the Abbotsford area.
Dunedin bus services were operating, but there were some delays due to icy road conditions. Two flights were cancelled at Dunedin International Airport this morning.
The Clutha District Council urged motorists to continue to take extreme care today due to further snow and sleet overnight, and ice covering roads in many parts of the district this morning.
Snowdrifts of up to 20cm are present in high areas in and around Clinton, including Slopedown and Owaka Valley. The council advised motorists to avoid any non-essential travel in those areas.
A number of rural roads in high country areas remain impassable due to snow. These include roads in Slopedown/Owaka Valley near Clinton, Hillend-Mt Stuart, Waipori, and Mahinerangi.
Clutha Valley and Clinton primary schools are closed today, but the rest of schools around the district remain open.
Apart from Danseys Pass, all roads within Central Otago remain open. Roading authorities are warning motorists of the likelihood of ice on the district's roads, especially on bridges, in shaded areas and on hills.
Snow has closed Danseys Pass for the past 10 days and it will remain closed today and be re-assessed tomorrow.
In the Queenstown area Arrowtown was again the hardest hit last night with snow, but all Wakatipu schools were kept open.
Main roads to Queenstown had been gritted and upon passing Lake Hayes the roads were clear of all snow.
Chains were essential for vehicles driving over the Crown Range from Wanaka and were to be worn up Coronet Peak and Remarkables ski fields.
Snow and ice patches were spread throughout the Dalefield area especially Littles Rd.
Overnight the temperature in Queenstown remained around 2 degrees and today will receive a high of 5.
Police are urging people to take special care after a lucky escape this morning near Arthurs Point.
Constable Aaron Redaelli, of Queenstown, said a car travelling towards Queenstown seemed to have come around the corner before Cavells bridge and has gone through a fence and down the bank.
The vehicle had driven away before emergency services arrived.
Const Redaelli urged motorists to take care in these icy conditions as there was plenty of black ice.
Southwesterlies pounding Otago and Southland with snow, rain and high winds are expected to continue today and warnings have been issued that extreme care is needed on the regions' roads because of widespread winter conditions.
The MetService issued another weather watch yesterday, warning southwesterlies could become severe from this afternoon through to tomorrow morning for Clutha and Dunedin.
There was also potential for heavy snow for parts of Southland above 200m, and the Catlins.
Snow showers were expected to continue in Central Otago and the Lakes district.
Consultant hydrologist Dave Stewart said such a south or southwesterly weather pattern typically hit Southland, South Otago and inland parts of Otago harder than Dunedin.
"Dunedin's not exposed, so it will stay reasonably dry. There will be a shower or two, but it will not get hammered like further south."
However, it was typical for winter storms to hit the region at this time of year, he said.
The weather started to close in yesterday afternoon. Higher areas around Clinton and Owaka were the hardest hit, with up to 10cm of snow in places.
John Latta, who farms between Owaka and Clinton, said it snowed for most of the day and farms closer to Clinton received heavy falls. By late yesterday afternoon more than 4cm of snow had fallen on his property.
The Clutha District Council advised motorists to take care around the Caberfeidh-Gibbs Hill area south of Owaka, Owaka Valley Rd from Chloris Pass Rd to Clinton, and the Puerua Valley.
Roads around Slopedown, near Clinton, were limited to four-wheel-drive vehicles.
Schools in Queenstown and Arrowtown opened late yesterday after snow settled on roads.
Some bus pupils from Clinton Primary and Catlins Area Schools were sent home early, before conditions became treacherous.
