Updated | Surfer's lucky escape when shark bites board at Cronulla

A surfer had a lucky escape when his board was believed to have been bitten by a shark at Cronulla on Sunday morning.

Bate Bay beaches were closed immediately after the incident, which occurred about 8am.

Donna Wishart, a spokeswoman for Surf Life Saving NSW said, "A surfer was bumped by a shark - he was not hurt, but it grabbed his board".

"Beaches are closed for 24 hours," she added.

A photo of what was said to be "the board in question", and showing what appeared to be a bite mark, was posted on Leader Facebook page.

Lifeguards initially doubted whether a shark was responsible and other board riders speculated the damage could have been caused by a patch of protruding reef.

However, officers from the NSW Department of Primary Industries inspected the board and confirmed the damage was consistent with a shark bite.

Ms Wishart said, "It was not so much an attack, but definitely an encounter".

"He felt the board being pulled out from under him, but didn't really see anything," she said.

A spokeswoman for the NSW Department of Primary Industries said there was no evidence the shark involved in the incident was a tagged shark.

"The nature of the incident, where minor damage to the board was sustained, does not allow for such a determination, or determination of species, to be made," she said.

"NSW DPI continues to work with other agencies including NSW Police Marine Area Command and Surf Life Saving NSW, and will continue to monitor the situation and provide any technical advice and resources if required."