Canterbury and Otago motorists are being warned to expect treacherous road conditions on Tuesday, as temperatures plummet below zero, causing frosts and more snow falls.
In Canterbury, snow is expected to fall to about 200m and police are urging all motorists to adapt to the winter conditions.
The situation is similar in Otago, with police warning of black ice. In Central Otago, temperatures are expected to drop to about -10degC.
Most of the South Island highways closed by winter's first big snowfall reopened on Monday, including Dunedin's northern motorway, which closed after several trucks slid off it.
A hailstorm which hit the city overnight and on Monday morning forced the closure of all primary schools for the day, cut power and closed many roads.
Many had reopened but roading crews are having to clear snow up to 1m deep in parts of the Strath Taieri region inland from Dunedin.
Dunedin City Council roading maintenance engineer Peter Standring said it had been a busy day for contractors.
"Certainly a lot of roads up Strath Taieri which are quite a challenge. They've actually probably got the deepest snow up there at the moment.
"We've reports of some of the drifts being up to 1m. That's not too uncommon up there when we do get snowfall but it will take a wee bit to clear that."
Mr Standring said he did not know when the roads between Dunedin and Middlemarch would reopen.
Up to 12cm of snow fell in high areas of South Otago, with the heaviest falls at Hillend, Clinton, Milton and Moa Flat.
Power has been restored to everyone in the south who lost it as a result of the storm.
Big dump at Frankton
Queenstown Lakes District Council said 15cm of snow fell on the ground outside Arrowtown, and up to 50cm in Frankton.
Council spokesperson Michelle Poole told Radio New Zealand's Morning Report programme snow fell to lake level across the Wakatipu basin and the Wanaka area.
Seven flights were cancelled at Queenstown Airport, which received 30cm of snow overnight, but all flights have since resumed.
Schools in the Queenstown region were closed, including Arrowtown School, Wakatipu High School, Remarkables Primary School, St Joseph's School, Queenstown Primary and Kings View School, while Wanaka Primary School and Mt Aspiring College in Wanaka were closed because of black ice.
Arthur's Pass open
Arthur's Pass, in the central South Island, will remain open to all traffic on Monday night.
A massive slip about 1km west of Otira on State Highway 73 closed the road on Friday. Single-lane access was opened up through the area at midday on Monday.
Police said motorists should take care and should observe the 30kmh speed restriction around the slip site.
Meanwhile, the strong, cold south-westerlies have pushed into Christchurch, with snow predicted to fall as low as 200m in Banks Peninsula as the winter storm moves north.
Chains are required for motorists driving between Little River and Barrys Bay on Banks Peninsula.
MetService duty forecaster Leigh Matheson said parts of Canterbury could experience double digit minus temperatures overnight on Monday.
Lower North Island battered by wind
In the lower North Island, strong winds played havoc in Wairarapa and Tararua.
Up to 4000 properties were without power at different stages during the weekend after strong winds tore down power lines.
PowerCo network operations manager Dean Stevenson said about 350 properties in the Wairarapa would remain without power on Monday night.
The cold weather has not closed any North Island roads but there is a strong wind warning for the Desert Road, and there are also snow flurries around the Desert Road and Waiouru.
Severe frosts are expected on the Central Plateau, and snow showers on the Rimutaka hill to about 600m.