Contractors are working to grit and clear Dunedin's snow-covered city streets as the severest cold snap in 16 years hits the country.
Most of the main routes through Dunedin are clear of snow and ice, although traffic remains light through the central city as many residents chose to follow the advice of emergency services to avoid uneccessary travel.
About 90 people remain stranded in Waitati, after they were forced to leave their vehicles on State Highway 1 on the northern motorway yesterday afternoon, when a fierce hailstorm followed by snow and sleet showers hit the Kilmog Hill about 1pm.
Air travel out of the South Island has been badly disrupted with flights from Christchurch, Dunedin and Queenstown cancelled this morning. Flights at Invercargill airport were experiencing delays.
In Dunedin, several roads are closed due to snow and ice: Three Mile Hill, Mt Cargill, Castlewood Rd, Fea St, Corrie St, Drivers Rd, Pitt st and Royal Tce.
Beyond the city, snow on Otago's state highway network had been packed to ice by traffic, Roger Bailey, of New Zealand Transport Agency, told odt.co.nz.
Early this evening, State Highway 87 from Outram to Middlemarch and State Highway 85 from Palmerston to Kyeburn were still closed. Caution was advised on State Highway 1 from Palmerston to Dunedin, and motorists travelling on State Highway 8 from Alexandra to Raes Junction and Shate Highway 8 Omarama to Tarras (Lindis Pass) were advised to carry chains.
The Crown Range was open, but motorists were advised to carry chains.
Motorists were warned they should watch for grit and ice in shaded areas throughout Otago and Southland, and those planning to travel alpine passes of through Central Otago should carry chains.
The Southern District Health Board postponed most elective surgery today in Dunedin and Invercargill, the exception being patients already admitted for procedures at Dunedin Hospital.
In Queenstown, court has been cancelled for today and tomorrow.
Meanwhile, Christchurch has felt the brunt of the wintry blast, with near-blizzard conditions overnight causing many road closures and the shutdown of the quake-devastated red zone this morning. The city was expected to receive another "surge of snow" until about mid afternoon.
A foot of snow has already forced most workers to stay at home, closed Christchurch Airport and forced the cancelled of all elective surgery and outpatient clinics.
MetService forecaster Paul Mallinson said New Zealand had not had a nationwide cold snap of this severity in 16 years.
"It's a real cold one, a 15-to-20-year outbreak ... The last time we remember snow getting to this low in Wellington is around 1995."
MetService has lifted heavy snowfall warnings for Fiordland, Southland, Otago, and the west of Nelson.
Snow has also fallen in unusual parts of the country this morning, with the Bay of Plenty's Kaimai Ranges, Taupo and Taranaki all suffering from the wintry bite.
WeatherWatch head analyst Philip Duncan said had been unconfirmed reports of snow flakes falling on Auckland's Mt Wellington.
He said reports of snow fall were coming in thick and fast this morning.
"We've had reports of snow in Lower Hutt and Wellington overnight and this morning. We've got reports of snow settling on the cars in Masterton for the last hour, snow at very lower levels at Lake Taupo and in Taupo itself, snow in Hawera, Stratford, Taranaki," Mr Duncan said
Mr Duncan said there had also been one unconfirmed report of snow near Raglan, in Waikato, however there had been very heavy hail in the region.
"This isn't the snow storm of the century ... but what makes this system different ... is the low snow level, which is sea level across much of southern and eastern South Island and to very low levels right across the lower North Island. This is a national event," Mr Duncan said.
In Dunedin, police were kept busy dealing with minor road accidents brought on by the treacherous driving conditions around the city yesterday. Seneior Sergeant Brian Benn said a number of cars had slipped off steep roads in the city's hill suburbs.
Police were taking a ''common sense'' approach to stranded vehicles around the city suburbs, which in many cases had been abandoned by drivers after road conditions proved too precarious for safe travel, he said.
''Once the thaw starts than we would prefer owners [of vehicles] to take steps to retrieve their property,'' Snr Sgt Benn said.
Despite the hazardous driving conditions, there had been no major incidents on Dunedin roads.
''There has been nothing too serious from the snow and ice around the city and overall we are pleased with the the behaviour of most motorists,'' Snr Sgt Benn said.
There had been complaints made to police about the antics of some drivers around the city, and also from people who had been on the receiving end of unwarranted snowball attacks in North Dunedin, he said.
''We have to prioritise the incidents we can get to and occassionally some of these complaints can be time-consuming to deal with,'' Snr Sgt Benn said.
The northern motorway out of Dunedin on State Highway 1 remained closed to motorists this morning, after snow and ice shut the route to Waitati down at about 1pm on Sunday, he said.
About 90 people were taken from their stranded vehicles on the northern motorway and transported to Waitati, where they spent Sunday night at the township's hall and local marae, Snr Sgt Benn said.
''They have been looked after by the locals there and by all accounts, the community spirit is alive and well,'' he said.
Kane Baas of bus operator Passenger Transport-Citibus told odt.co.nz that they are gradually expanding bus services to other flat suburbs including St Kilda and North East Valley as conditions permit.
Free services had been been run "just to get people out of the cold," he said.
- Matt Haggart/Additional reporting the New Zealand Herald