Police are urging drivers to take extra care on the roads, with icy conditions across Canterbury

A number of crashes have already been reported, noting the conditions as a factor - no one's been seriously injured.

In Dunedin, widespread black ice has forced a number of schools and education provider to delay their starts, until 10am.

Local, Megan says her husband has described the roads as a sheet of ice - the worst he's seen.

She says it's not just in the usual spots, it's all over the road.