Senior Sergeant Steve King, of the Canterbury Highway Patrol, said most drivers heeded warnings to drive cautiously this morning and kept the number of crashes to a minimum, with just eight minor crashes reported to police this morning, with no injuries reported.
"Conditions have definitely been challenging in places.
"Fortunately, most drivers have been doing the right thing - keeping speeds down, extending following distances and driving cautiously. It's been good to see motorists taking those safety messages on board.
He said the situation was helped by lower traffic volumes this morning, but warned that the difficult conditions would continue for some time.
"It's important that drivers remain cautious throughout the rest of today and overnight. There is still ice on many roads, and if melting snow refreezes then drivers may face similar hazards overnight and in the morning. Rural locations and shaded areas are particularly at risk.
"So our message is the same - assess your local conditions, and if the roads are icy, try to avoid non-essential travel. If you are driving, please drive slowly, extend following distances, be patient and allow extra time for your journeys."
Weather causes more disruption
There has a second day of disruption across parts of the South Island as the aftermath of yesterday's snowy weather continues to be felt.
Power is still out for about 900 customers around Canterbury, with pockets of outages in the Harewood, Weedons, Kimberley, Hororata, and Annat areas, down from 1700 customers without power this morning.
Orion chief executive Rob Jamieson said repair crews have been working to restore power from first light.
"We hope to restore power across our network by the end of today if the weather holds and our crews can safely access all areas. Large amounts of snow mean it's difficult for our teams to reach some parts of the network," Mr Jamieson said.
"Almost all of the power cuts have been caused by trees and branches weighed down by snow, falling on power lines. These cuts highlight how important it is to keep trees trimmed and well away from overhead lines."
Mainpower reported about 600 properties in North Canterbury, including Hanmer, Rangiora and inland Kaikoura, lost power overnight.
Fortunately the snow showers cleared for the South Island overnight, MetService forecaster Leigh Matheson said.
"It was really only the areas north of Christchurch and up into the Marlborough mountains that were getting snow yesterday evening," Ms Matheson said.
Inspector Pete Hegarty said grit trucks have been working in central Christchurch throughout the night, but the whole region is slippery and he urged those who do not need to travel to stay at home.
Christchurch Airport remains open, however there are warnings of disruptions to flights due to ice and freezing temperatures. The mercury dropped to -5.3 degrees celsius at the airport early this morning, but is now about 0 degrees celsius.
Passengers were recommended to check with their airline before heading to the airport.
Some bus services in Christchurch are set to resume this afternoon after buses were off the roads this morning.
The snow has also forced the closure of schools, university and council offices, and the cancellation of club meetings across Canterbury.
Canterbury University and Christchurch Polytechnic Institute of Technology campuses are to remain closed all day.
New Zealand Post shops will be open in Christchurch today, however deliveries in the city remain suspended. Delays are expected for mail deliveries in Ashburton, Nelson and Blenheim, while Greymouth services are back to normal.
Plunket has suspended all services in Canterbury and Mid Canterbury regions again today due to the road conditions.
Fallen trees and heavy snow has blocked roads across the South Island.
State Highway 65 from Maruia to Shenandoah, SH63 from St Arnaud to the Wairua Valley, SH7 from Springs Junction to Reefton, SH7 Lewis Pass, SH73 from Arthur's Pass to Otira, SH73 Porters Pass, and SH7 from Springs Junction to Reefton are closed this morning.
Queenstown Lakes District Council has reported there are small amounts of frozen snow on the Crown Range, and ice on Arthurs Point and Glenorchy roads and Lindis Pass.
Parts of the main hill roads in Christchurch will also be assessed first thing this morning.
Crews have been out overnight clearing any remaining snow and gritting ice.
NZTA spokesman Barry Stratton said they will be working as quickly as possible to get the roads operational again.
"We'll be assessing first thing in the morning and the likelihood of the passes opening early are small. It's probably going to mid-morning to late-morning before we can see any movement."
Fire Service southern communications shift manager Brent Dunn said crews had several weather-related callouts overnight, mainly for trees falling on powerlines.
Meanwhile the clean-up also continues across the Nelson/Tasman region, with snow still blocking roads, while heavy rain yesterday also flooded roads in the Murchison area. Howard Valley Road, near Murchison, was washed out in yesterday's deluge.
