Five people, including a baby, have been injured in a car crash near State Highway 1 in the Horowhenua District.
The incident happened just before 5pm on Koputaroa Rd, Koputaroa.
One patient was airlifted to Palmerston North hospital in a serious condition after becoming trapped in their vehicle.
Police officers at the scene removed the person from the vehicle, said a police spokeswoman.
Three adults and a baby who were travelling in the other vehicle have been taken to Palmerston North Hospital with moderate injuries.
Police, ambulance and fire were at the scene.
The crash has closed the northbound lane Koputaroa Rd and a section of SH 1 for the helicopter to land.