Police are urging campers to be vigilant after a man was killed when he was run over by his unattended vehicle at Wattletree Beach camping ground at Barooga in southern New South Wales.

The 20-year-old Victorian man was with his partner on Saturday night at the camp site when his parked four-wheel drive rolled down an embankment and ran over him while he was sleeping.

Other campers performed first aid on the man, but he died at the scene.

Map Wattle Beach camping ground, where a man was run over by his own vehicle

Chief Inspector Kim Sorensen said campers should try to be vigilant about small details in order to prevent accidents.

"If you are parking a vehicle on a slope, park it across the slope rather than straight up and down it.

"Leave it in gear, hand brake on and chock up the wheels, so there is no way that if any one of the systems fail that you end up with a tragedy.

"As emergency services personnel will tell you need to be vigilant about everything you've got at your campsite, be it your fire, be it your vehicle, be it your boats."

Officers from the Murray River Police district are investigating the incident.

A report will be prepared for the coroner.