A person is seriously injured after a truck rolled on State Highway 23 between Raglan and Hamilton.
The crash, which occurred about 8.30am, has closed the road.
The truck rolled and a person was trapped inside, Fire and Emergency shift manager Kaisey Cook said.
The person has now been freed, a police spokesperson said.
Two ambulances were on scene treating a person in a serious condition, a St John spokesperson said.
The crash occurred on the deviation, a stretch of State Highway 23 that winds over a range between Raglan and Hamilton.
Police said there were reports of oil spilt over the road, and the road is now closed.