A serious crash north of Waiouru has closed the Desert Road (SH1).
Two cars collided at 1.30pm and two occupants of one vehicle were being cut from the wreckage, police said.
One person from the second vehicle was being flown from the scene and the road closure was to allow the helicopter to land. The barriers at each end of the highway had been shut.
Police said they would attempt to open one lane once the helicopter had left the area.
Initial reports indicated two people had received serious injuries.