Police are probing the cause of a crash that killed three motorcycle riders

The triple-fatal collision happened on State Highway One in the central North Island near Utiku, south of Taihape, on Saturday morning.

A fourth motorcyclist is in hospital in a critical condition.

The Road Pirates Motorcycle Club president's told our newsroom Police are investigating whether the car involved was on the wrong side of the road.

Police have said it's too early to comment.