Bronte beach lifeguard Chris Chapman said the man was having an early morning surf when the two-to-three metre (six-and-a-half to ten foot) shark attacked.

Chapman said the surfer, aged in his 30s, told him the shark had latched onto the front of his board, which he then pushed into the predator's mouth.

"He was very calm, surprisingly, he took it quite well," Chapman told ABC radio.

"He just came up and said, 'look at my board'. He said he kind of shoved the board into the shark's mouth just to kind of put himself at a bit of a distance from the shark but he was very calm."

Chapman said the surfer was back in the water a few hours after the attack.

Australia has had nine fatal shark attacks since 2000, the most recent off Western Australia last month.