A 10-year-old boy with serious head injuries is undergoing surgery following an accident involving two cars and a truck north of Waikanae on the Kapiti Coast.
Police say he was the passenger in a car which had stopped on State Highway 1 and was indicating to turn into a driveway.
A small truck went into the back of the car pushing it into the south bound lane where it collided with another car.
Police say two adults and three children were travelling in the car and they were all admitted to hospital.
A helicopter was used to transport the 10-year-old boy to hospital and a seven-year-old girl received spinal injuries.
Two people in the truck and two people in the other car received medical treatment at the scene.
Police say it appears alcohol was not involved in the crash, but they say speed, road conditions and the drivers will be investigated before it's decided if charges will be laid.
The crash closed State Highway One for about four hours and traffic was backed up in both directions, even though a diversion was put in place.