One killed in car crash on national park road in Sydney's south

One person has died in a crash on a national park road in Sydney’s south.

A NSW Police spokesperson said the single-vehicle crash had closed Farnell Avenue, in the Royal National Park in Sutherland, in both directions.

Emergency services were called to the scene about 7.40am, a NSW Ambulance spokesman said.

Police believe the male driver might have suffered from an ongoing medical condition.

It is believed the car veered off the road and rolled, crashing into an embankment.

An investigation into the crash is underway, with motorists in the area advised to check livetraffic.com for updates.