Police were trying to free the occupant of a vehicle that rolled in the Christchurch suburb of Burwood tonight.
Shortly before 9pm emergency services were called to a crash in which a vehicle rolled on Cresswell Ave.
Police confirmed, at 9.30pm, one person had been trapped in the vehicle as they attempted to free them.
Just after 10pm a St John Ambulance spokeswoman said the person had been taken to Christchurch Hospital in a critical condition.
Both Cresswell Ave and New Brighton Rd had been closed, and diversions were in place.
Motorists were asked to avoid the area.