The driver of a white Porsche has fled the scene after the car crashed through a metal railing and over a ledge into a Burswood car park.

Police are trying to determine whether speed was a factor in the crash at Bow River Crescent overnight.

The street is in a new housing estate adjacent to the Crown casino complex.

The vehicle dropped three metres, nose-first, into the garden bed of a car park at the casino, and the driver fled the scene.

Police said a passenger in the car was not injured.

All the car's air bags were activated by the impact and the vehicle landed back on its wheels.

Debris from the crash damaged a silver Mazda 2B hatchback parked in the carpark.

A police guard remained with the car until a tow truck arrived.

The 2010 model car, valued at more than $150,000, is a write-off.