A motorcyclist has died from injuries sustained in a head-on collision with a car on State Highway 1.

The rider was airlifted to Waikato Hospital in critical condition following the crash at Tamahere about 1.20pm yesterday.

The serious crash unit is investigting the cause of a fatal motorbike accident. File photo.

The motorcyclist died overnight.

Police are investigating the cause of the crash and say early indications are that both the motorcycle and the car crashed head-on.

The crash closed the stretch of highway for a while and road works in the area added to the delays.

The serious crash unit is investigating the crash.

Police are appealing for any witnesses to the crash and asked people, who have not already spoken with police, to contact them on 07 858 6200.

Alternatively, information can be left anonymously via the Crimestoppers 0800 555 111 line.