Concrete spilt on Auckland motorway

Police say the clean-up could take until 5pm. Photo / File

A concrete mixer has left a 1km long trail of wet concrete on a motorway north of Auckland this afternoon.

The truck dropped its load on State Highway 1, between Orewa and Redvale about 2.50pm, said Police Northern Communications shift inspector Cornell Kluessien.

"The traffic is flowing, at this time of day it still works but in an hour it would be mayhem."

Mr Kluessien said the clean-up could take until 5pm.