Shark attacks
A surfer escaped with cuts to his leg on Monday in the third shark attack off New South Wales state north of Sydney in a month.

The attacked occurred at Byron Bay, 22 miles north of Ballina, where a 25-year-old man sustained minor leg injuries while surfing with friends on October 12.

Beaches in the area, around 500 miles north of Sydney, were closed for at least 24 hours after the early morning encounter, with the victim taken to hospital by a friend.

"It is believed that the shark emerged from under the man while he was waiting for a wave," Surf Life Saving New South Wales said.

"The man's surfboard took the brunt of the impact with the man also suffering minor lacerations to his leg during the incident."

It was not known what type of shark was involved.

A surfer who administered first aid at the scene, Geoffrey Knapp, said the victim had been lying on his board when the shark attacked.

The victim "clearly saw the tail and he got the impression that the shark was trying to knock him off his surfboard and roll him over," Mr Knapp told ABC News.

On September 26, a 17-year-old surfer required stiches to close a leg wound after he was bitten by a shark off Ballina.

A 41-year-old Japanese surfer was killed by a shark off Ballina last year.

Efforts to contain the marine predators have so far proven difficult, with a shark eco-barrier trial in the Ballina area recently scrapped due to rough sea conditions.

Hundreds of protesters gathered at Ballina on Sunday to demonstrate against government plans to place anti-shark nets along beaches around Ballina.

The nets, which are suspended from floats and run parallel to the coast, are not complete barriers to sharks and kill a wide variety of marine life. Environmentalists oppose them.

Of the 14 unprovoked shark attacks off the New South Wales state coast in 2015, most occurred along a 37-mile hotspot from Evans Head to Byron Bay which includes the town of Ballina.

Experts say shark attacks are increasing as water sports become more popular and bait fish move closer to shore, but fatalities remain rare.