Black ice has caused several crashed on State Highway 5 this morning, with parts of central North Island experiencing temperatures well below zero.
Patches of black ice on the Mamaku Ranges, SH5 have caused several crashes this morning, police said.
Road crews were heading to the area to spread grit and reduce the affect of the black ice.
Police were telling people to slow down and take caution around the black ice and pay strict attention to road conditions.
Temperatures in Waikato were well below zero overnight and this morning.