A teenage girl has been flown to hospital after a car crash at Koo Wee Rup.

Paramedics were called to the scene beside Koo Wee Rup Road just after 1pm on Thursday.

Intensive care paramedic David Kervin said the 15-year-old girl was incredibly lucky not to have been more seriously injured.

"It appears as though the car has come off the road and through a fence," Mr Kervin said.

"One of the fence posts and part of the railing had actually come through the car’s windscreen and just missed the girl's head.

"The post was about five metres long and about 150 millimetres thick."

The girl suffered injuries to her chest and abdominal area. She was flown to the Royal Children's Hospital in a stable condition.

Mr Kervin said the girl and the driver, believed to have been in his late teens, were both distressed by the near-miss.