UPDATED 4.54PM: All lanes have reopened on the Princes Highway near Heathcote but southbound traffic is backed up over five kilometres after a fatal car crash earlier.
A woman died in the two-car crash.
Police said a northbound car crossed the grass medium strip and collided with a car travelling south.
The woman who died was a passenger in the southbound car.
An ambulance spokesman said four women were involved in the crash, and an emergency helicopter crew and six ambulance crews treated the injured at the scene.
The two occupants of the other car were taken to St George Hospital with non-life threatening injuries.
Drivers are advised to allow extra travel time.