Woman, child killed in NSW highway smash

A woman and child have been killed in a crash on the Princes Highway on the state's south coast, while another child is fighting for life.

Police say a car with three occupants collided with a semi-trailer north of Berry about 11.45am on Tuesday.

The female driver and a child died at the scene, police said.

A girl in the vehicle, aged in her early teens, had to be freed from the vehicle and has been airlifted to Sydney's Prince of Wales Hospital in a critical condition, a NSW Ambulance spokesman said.

It's believed the three occupants of the car are related.

The truck driver was not injured and the highway remains closed in both directions, with motorists warned the closure will last several hours.