"Tonight and over the weekend, we are expecting very low temperatures," Kirk said.
"Particularly where the roads get no sun, motorists can expect black ice on our roads day and night."
Police ask that all motorists slow down, take extra care on bends and corners, and to buckle up at all times.
The Metservice is tonight warning motorists of snowfall expected around Arthurs Pass and Milford Rd tomorrow morning.
At Arthurs Pass snow was expected from 8am to 2pm tomorrow with the possibility between 1cm and 3cm of snow may settle on the road above 700m.
On Milford Rd, the Metservice predicted between 1cm and 2cm may accumulate on he road above 700m between midnight and 9am tomorrow.
Icy conditions were also likely at lower altitudes making driving hazardous.