Police are investigating whether a French student who plunged 40 metres off a cliff in the Royal National Park was taking or posing for photographs when he lost his grip and fell to his death.

Fabien Ardoin, a 23-year-old University of Wollongong student, was believed to be hanging from a ledge in the park when the sandstone crumbled and he fell.

Mr Ardoin's traumatised girlfriend and six other friends were with him when he fell about 10.30am on Sunday. His family in France were notified of his death overnight, a NSW Police spokeswoman said.

The accident occurred on a section of The Coast Track near Wedding Cake Rock, a popular spot south of Bundeena where bushwalkers often stop to take and pose for photographs.

The police spokeswoman said officers were investigating whether the man was taking photographs with his friends when the accident occurred.