Black ice on Northland road

Two vehicles have crashed off a Northland road this morning after striking black ice on a bridge.

Police are cautioning drivers to take care on State Highway 12 near Whirinaki after the cars ended up off the road just before 8am.

Northland police spokeswoman Sarah Kennett said the bridge could cause problems this week if there continued to be frosty conditions.

One of the drivers was treated for cuts to his head by St John staff.