Paul Kenny, 51, was attacked on Saturday morning off Samurai Beach at Port Stephens after he went for a 7am swim.

"I went to catch the last wave back in, put my head down and headbutted the shark," Mr Kenny told AAP from his John Hunter Hospital bed, after receiving almost 20 stitches in his right bicep.

"I didn't know it was there and couldn't see it because it was churned up white water."

Mr Kenny, who works in the mines at Muswellbrook, said the shark immediately latched onto his right arm.

"So I started hitting it and punching it to get it off," he said.

The seasoned surfer was about 50 metres from the beach and was understandably scared.

"I didn't know where it was and if it was going to take my legs," he said

After he made it safely to shore, some people who had witnessed the attack helped by retrieving a bandage from his nearby campsite, where he'd been staying with his wife. He was then rushed to hospital.

The Bateau Bay resident suspects he was bitten by a bronze whaler. He's sure it wasn't a great white shark.

Mr Kenny is a volunteer at Terrigal Surf Life Saving Club where he usually drives the jetski and helps others in trouble.

He told AAP he doesn't have any ill feeling towards the shark.

"I was in his world. He was just going about his business and I headbutted him so he retaliated."

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 earlier in the week.

"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.

The beaches were closed again on Saturday after the attack, a Department of Primary Industries spokeswoman told AAP.

Australian Associated Press