Police say a seven-year-old boy has escaped serious injury after a four-wheel drive went over a cliff at Austinmer, south of Sydney.

About 9.35 AEST this morning, the car was parked at the top of a driveway on Mountain Road.

The boy went in to a house with two adults, but a few minutes later the adults realised he was missing.

Witnesses have told police they saw the child in the car as it rolled down the driveway, went through two fences and down a small embankment.

It is believed the boy was thrown from the four-wheel-drive and landed in lantana.

The car then went over an eight-metre high embankment to the beach below.

Police say the child has cuts and bruises and has been taken to Wollongong Hospital for a check-up.