Update 11.32am: NSW Ambulance said two people have been been taken to Shoalhaven District Hospital following the accident on the Princes Highway at Tomerong.
They were both was conscious and breathing.
An ambulance spokesperson said three people were in the vehicle at the time of the crash.
The other passenger was stable with no serious injuries.
11.15am: Emergency services are on the scene of the accident on the Princes Highway at Tomerong.
The accident happened about two kilometres south of the Hawken Road turn off around 11am on Thursday.
Traffic is still moving slowly on the highway but has been reduced to one lane both north and south.
Ambulance paramedics are treating on of the occupants of the single car accident, which is believed was traveling north but left the roadway and struck a tree.
Earlier reports suggested the car was on fire but has since been extinguished.
Rural Fire Service crews and police are on the scene.
Please take care in the area.
Earlier: Take care on the Princes Highway near Tomerong after a motor vehicle accident.
Emergency services are responding to the accident between Hawken Road at Tomerong and Turpentine Road.
It is understood a car has left the roadway and collided with a tree and might be on fire.
The two occupants have escaped the vehicle.
Tomerong and St Georges Basin Rural Fire Service crews are on the way.
Take care in the area or avoid if possible. Expect traffic delays.