Three teenagers have been seriously injured in a crash at Nana Glen.

Emergency services were called to East Bank Road, Nana Glen, following reports of a single-vehicle crash.

It is believed the driver of the Volvo sedan, an 18-year-old man, failed to negotiate a bend, left the roadway and struck a tree, trapping himself and his two female passengers, aged 16 and 17.

The three occupants remained trapped in the vehicle for an hour and a half before being freed by emergency services.

The P2-provisional driver and his 16-year old passenger were both treated for crush-related injuries before being airlifted to hospital in a critical condition.

The man was taken to Gold Coast University Hospital while the younger passenger was transferred to John Hunter Hospital.

The 17-year-old passenger was transported by NSW Ambulance to Coffs Harbour Base Hospital with serious leg injuries.

Officers attached to Coffs-Clarence Police District established a crime scene, which was examined by specialist police from the Crash Investigation Unit.

Police are investigating whether speed may have been a factor.