Three people are in hospital with serious injuries after a crash on State Highway 16 north of Helensville this morning.
Police said they were called about 6.20am to the crash where two cars had collided head-on at a bend in the road.
The male driver of a southbound car and the two women in the northbound car were seriously injured and taken by ambulance to Auckland Hospital.
Another northbound car travelling north swerved to avoid the crash and went into a ditch, police said. The driver of that car is not injured.
The highway was expected to remain closed until mid-morning.
Police said it was too soon to say what caused the crash.