SYDNEY (AFP) - A surfer was severely mauled by a shark off Australia's east coast, officials said on Sunday (Dec 9), the latest in a series of attacks in recent months.

The 36-year-old was surfing near Scotts Head Beach some 490km north of Sydney in the morning when he was bitten, New South Wales state police said.

"The man suffered a severe leg injury below his knee on his right leg," a New South Wales Ambulance spokesman told AFP. "He had five deep lacerations and he suffered a lot of blood loss."

He was in the water with several other surfers when he disappeared, Surf Life Saving New South Wales said.

"One of them had seen him disappear under the water, with a flume of water spraying up and then the victim lifted his arm up to indicate he was having a problem," Surf Life Saving spokesman Donna Wishart told Australian national broadcaster ABC.

The man was flown to a hospital in serious condition. Officials said it was not yet known what shark species was involved.

The attack was the eighth off Australian beaches in three months, amid public debate about how to reduce the risk of encounters between sharks and the growing number of people using the ocean for leisure.

New South Wales, Australia's most populous state, has trialled non-lethal measures such as aerial drones to track shark movements and "smart" drum lines that alert the authorities to their presence.

Australia has one of the world's highest incidences of shark attacks, but fatalities remain rare.

There have been 16 "unprovoked" shark attacks off the vast continent's coast this year, including one death after a swimmer was mauled by a shark in the Whitsunday Islands in early November, according to data from Sydney's Taronga Zoo.