State Highway 1 is closed in both directions between the Pokeno on ramp and off ramp, following a head-on collision between two cars this morning at about 10.50am.

Four people were injured in the crash.

One has been taken to hospital with critical injuries, one has serious injuries and two others have minor to moderate injuries.

State Highway 1 is expected to remain closed for the next couple of hours.

Diversions are in place through Pokeno, but drivers are warned to expect delays.

Southbound traffic is advised to come off at State Highway 2 and travel through Te Kauwhata.

SOURCE: New Zealand Police