Snow and ice warnings are being issued for roads around the country after five vehicles crashed this morning.
Five vehicles crashed on North Road in Lorneville before 7am.
No one was injured.
It appeared the vehicles had hit ice before skidding off the road, police said.
They urged motorists in icy areas to drive slowly.
There are also snow warnings in place for State Highway 1 between Dunedin and Palmerston.
Rain, snow and frosts tonight make tricky conditions on the roads. Image shows rain and frosts - black ice possible where they overlap. ^TA pic.twitter.com/TfGIaX1dLV— MetService (@MetService) July 28, 2017
Meanwhile, emergency services worked to free a critically injured person from a car that crashed into a tree on the Coastal Highway in Redwood Valley, near Nelson, this morning.
Police said the other occupant was out of the car and ambulance staff were on the scene.
The crash, which police were alerted to shortly after 7.30am, had closed the highway between Maisey and Redwood roads.
The Transport Agency said drivers needed to continue to drive to the road conditions, as bad weather continues to lash parts of the South Island.
All alpine passes and the two routes to Kaikōura are open, with road crews working in sub-zero temperatures this morning.
The agency said people should check road conditions on its website, before they travel.
Forecasts are for very cold overnight temperatures in parts of the South Island, which could mean more ice and black ice tomorrow and this weekend.
Snowfall warnings for North Island
MetService reports that a brief period of snow showers down to 400m is possible tonight on the Napier-Taupo Road, State Highway 5.
On the Desert Road, State Highway 1, snow showers are expected to affect higher parts of the road from about midday today until Saturday morning.
And showers are expected to turn to snow above 300 metres later today on the Rimutaka Hill Road, State Highway 2.