An Australian surfing champion fought back against a shark attack on live television during a competition in South Africa on Sunday, escaping from the terrifying scene without injury.

Mick Fanning, 34, was competing in the final heat of a world tour event at Jeffrey's Bay in the country's Eastern Cape province when a looming black fin appeared in the water behind him.

In a churn of water and spray, Fanning could be seen battling to fend off the shark.

"It came up and got stuck in my leg rope," he said in a television interview afterwards.

"I was kicking and screaming. I just saw a fin. I didn't see teeth. I was waiting for the teeth to come at me as I was swimming. I punched it in the back."

Fanning, a triple world champion nicknamed White Lightning, was sitting on his board in the water when the shark lunged at him, tipping him off the board.

He was taken out of the water by safety crews, and said he had only lost his leg rope.

"We've never seen anything that dramatic and that frightening," commentator Joe Turpel was quoted as saying.