Three teenagers are fighting for their lives after being injured in a high-speed crash in Sydney's southwest.
Witnesses have told police they saw the Mazda 323 and Diahatsu Charade travelling erratically at high speeds along the Hume Highway at Warwick Farm, at around eight o'clock last night.
At the corner of Cabramatta road the Charade broke heavily and crashed into a signal box - the other vehicle left the scene.
Three teenagers are in a critical condition - two 18-year-old males and a 19-year- old girl after being trapped in the car for an hour.
It's believed the driver was a p-plater.
Two north-bound lanes of the Hume Highway remain closed this morning.