A man has fended off a shark by punching it in the head when he was attacked at Port Stephens, north of Newcastle.
The man in his early 50s was attacked at Samurai Beach about 7am on Saturday, the state's ambulance service said.
"We believe the patient bumped into the shark while surfing at which point the shark spun around and latched onto his arm," ambulance Inspector Brian Knowles told 2GB radio.
"He then managed to punch the shark in the head and get away and escape to shore."
Eyewitness Garry Sharp told The Newcastle Herald he saw Saturday's attack unfold.
"I had just pulled up at Samurai to check the surf," he said.
"I had noticed the lone swimmer in the water and the next thing the shark appeared."
A NSW Ambulance spokesman told AAP the victim was "conscious and alert" when helped from the water.
He suffered an injury to his upper right arm and was taken to John Hunter Hospital in a stable condition.
The beach had only reopened on Friday after National Parks and Wildlife Service officers removed a large decomposed whale carcass which had washed ashore at neighbouring One Mile Beach.
"A 20-tonne excavator and front-end loader were used to remove the 10-tonne whale carcass to a local disposal site for burial away from the beach," a NPWS spokesman said on Friday.
It's thought the sperm whale carcass could have led to increased shark activity in the area.
