A 17-year-old female was driving a white Holden Barina on Bruxner Park Road with two friends, 14 and 15, about 10.30pm when she lost control of the vehicle around a sweeping bend just 400 metres from Sealy Lookout.
The car crossed to the incorrect side of the road and collided with a tree before spinning and sliding 20 metres down an embankment.
The two female passengers were freed from the vehicle immediately and taken to the Coffs Harbour Base Hospital with serious wrist, leg, and abdominal injuries.
The driver remained trapped inside the car for more than a hour, and after being freed by emergency services was conveyed to Coffs Harbour Base Hospital with very serious leg injuries.
She later underwent surgery. All three girls remained in hospital yesterday, the two passengers in a good condition and the driver stable.
Police investigations into the cause of the accident are continuing.