Police can confirm the driver of the ambulance involved in Wednesday morning's crash on Tirau Road, Cambridge has sadly died in hospital.

"The two-vehicle crash, involving a car and an ambulance, happened around 3:40am today and saw the driver of the car die at the scene," says a police spokesperson.

An initial statement from police said a vehicle had crashed into the back of an ambulance but Highway Patrol Sergeant Matthew Crossan said at the scene that the two vehicles collided head-on.

The ambulance had been heading south and the car heading north.

The driver of the car died at the scene, a police statement said.

The critically injured driver of the ambulance was airlifted to Waikato Hospital. Another ambulance staff member, who was inside the vehicle at the time, was moderately injured. The driver of the ambulance has now died in hospital.

"Police's thoughts are with the families of the deceased," says a police spokesperson.

The circumstances of the crash remain under investigation.