By 1.35pm all but one (SH87 Outram-Kyeburn) had reopened, but motorists were advised to take care owing to wintry conditions.
Meanwhile, the first flight of the day landed at Queenstown Airport as adverse weather affected flights around the South Island.
Jetstar flight JQ295 from Auckland landed at the airport at about 10.35am.
All other flights into Queenstown Airport on Tuesday morning were cancelled or delayed.
An Antarctic blast has swept up the South Island, bringing freezing temperatures and dumping snow.
Snow is blanketing much of the south, leaving numerous highways closed and even falling to sea level in Christchurch overnight and on Tuesday morning.
A number of arriving flights into Christchurch from Invercargill, Queenstown and Wellington were cancelled due to the adverse weather.
The Lewis Pass, SH7, from the Reefton, West Coast side over the Rahu Saddle, to the Hanmer Springs turnoff on the Canterbury side reopened at 10am.
"We are hopeful that snow conditions will ease today.
"However, wind chill is keeping temperatures very low and ice may continue in many places today and overnight to Wednesday," said Waka Kotahi journey manager Tresca Forrester.
"Please watch your following distances, slow down, turn your lights on and expect ice on some bridge decks and areas that get little sunlight. Grit trucks will be busy, expect to see snow ploughs and in some places chains may be needed," she said.
More than a thousand houses were without power in Canterbury on Tuesday morning.
UPDATE 10:20AM, TUE 29 JUN Due to a high number of State Highway closures & cautions in Otago/Southland, please delay your travel or take extra care. Remember to switch on your lights, increase your following distance & be prepared for unexpected hazards. https://t.co/Y5OcMy1CINpic.twitter.com/1AgXtnyNE7
— Waka Kotahi NZTA Otago & Southland (@WakaKotahiOS) June 28, 2021
731 houses in Akaroa, Chorlton, Duvauchelle, Le Bons Bay, Little Akaloa, Ngaio Point, Okains Bay, Robinsons Bay, Takamatua, Takamatua Bay were without power at about 7.30am.
At 11am, just 44 houses in the area were still without power.
Power was also out in 132 homes in the Halswell, Ladbrooks, Lansdowne, Lincoln, Prebbleton and Tai Tapu area but had been restored by 11am.
Owner of the Hilltop Tavern in Duvauchelle, Melissa Blanchfield said they have had between five and 10cm of snow this morning.
'We are getting more hail and snow at the moment so it's continuing to come."
Blanchfield said it is cold but she wouldn't say it's as cold as what they are used to.
"When we get snow here it tends to take away the real coldness that we can get."
Road crews were clearing snow in the area at about 9.30am.
Heavy snowfall warnings are in place for the Canterbury Plains north of the Rakaia River, including Banks Peninsula and Kaikōura south of the Clarence River.
As well as for Southland, north of Nightcaps and east of Wyndham, Dunedin, Clutha and Central Otago.
Heavy snowfall watches are in place for the Canterbury Plains north of the Rakaia River, including the Banks Peninsula and Kaikoura south of the Clarence River.
Heavy snow was possible in Taihape, around the Tararua Range and Banks Peninsula on Tuesday.
The wild weather has disrupted travel in both islands – with the Interislander ferry cancelling all sailings for today, while Air New Zealand cancelled 33 flights in and out of Dunedin, Invercargill and Queenstown yesterday.
A road snowfall warning is in place for the Napier-Taupō Rd (until midday Tuesday), Desert Rd (until 5pm Tuesday) and Remutaka Hill Rd (until 4pm Tuesday) in the North Island.
MetService forecaster Gerard Bellam said snow had fallen to low levels across the Southland and Otago, with blizzard-like conditions in alpine areas.
The polar outbreak had left snow falling down to sea level in Christchurch.
The bitterly cold air mass was now continuing on its northern track, bringing with it severe gales and large seas.
Snow and ice in Queenstown yesterday forced some drivers to carry chains and motorists across the Wakatipu Basin and in Wanaka were urged to watch for rockfall.
Yesterday morning, Treble Cone was coated in 15cm of snow on the upper slopes and Cardrona had received around 10cm.
Moke Lake in Queenstown, the Crown Range Summit and Ben Nevis Range were coated in snow.
Meanwhile, Waka Kotahi has urged motorists driving on SH11/Desert Rd and SH5 Napier- Taupō Rd today to prepare for winter driving conditions, including snow and ice.
Waikato system manager Cara Lauder said further road closures were possible and motorists should plan ahead and drive prepared with a spare tire, charged cellphone, blankets, snacks and a bottle of water in case they break down.
"Plan ahead, allow extra time for your journeys and drive to the road and weather conditions. Maintain a greater following distance between your vehicle and the one in front, slow down and be prepared for unexpected hazards."