Southern drivers are being warned to be on the look out for black ice on the roads.

Roads in the Dunsandel and the Burnham areas in Canterbury are slippery after a frosty night. There is also a lot of black ice on the roads in and around Dunedin, Mosgiel and Middlemarch. A motorist has already spun on ice and crashed on the Selwyn River Bridge on State Highway 1.

Police spokesman Hemi Waretini says drivers must drive carefully and to the conditions..

Last week, a bus carrying 13 tourists travelling to Milford Sound rolled on State Highway 94, killing a tourist. Black ice on the road may have been a factor in the crash.