An elderly man was critically injured in a head-on crash this afternoon which closed a section of State Highway 2 for about three hours.
The man had been trapped in his car after a collision with another vehicle on SH2, just north of Carterton at 2.45pm.
Police Sergeant Quentin Hoera said one vehicle had been travelling south and the other north when the crash occurred at the top end of the northbound passing lane.
The two vehicles involved each had one male occupant.
"Scene examination by the Serious Crash Unit will confirm this later in the investigation, but initial witness accounts suggest the southbound vehicle has crossed the centreline," he said.