The Desert Road in the central North Island has been closed by a crash just north of Waiouru. The barriers at each end have been shut.
Police say two cars collided at 1.30pm on Monday and two occupants of one vehicle are having to be cut free.
One person from the second vehicle is being flown from the scene and the road closure is to allow the helicopter to land.
Police say they will attempt to open one lane once the helicopter is clear.