Photo: Jack Edstein

A 65-year-old man has been attacked by what is believed to be a great white shark at Black Head Beach at Hallidays Point, north of Forster on the NSW Mid North Coast.

The victim, David Quinlivan, was flown to Newcastle's John Hunter Hospital. His injuries have been described as "severe but not life-threatening"

Mr Quinlivan, a member of the Black Head Surf Club, was the only one in the surf at the time. Bystanders helped him from the water.

A spokesman for NSW Ambulance said: "Information from paramedics at the scene suggests the man has a severe injury to his lower leg."

However, acting Inspector Mathew Hinton said his injuries were not considered to be life-threatening. Black Head's Warren Thompson told NSW Surf Lifesaving he saw the incident unfold from the sand.

"It would have been around 11.30 or so and I was down there checking out the surf conditions when I saw the paddler fall off the side of his ski," Mr Thompson said.

"Something clearly had knocked him off the ski and he was hanging on to the edge. There were a couple of us on the beach and we all just sprinted to the water to see what we could do to help.

Asked about the attack on Friday afternoon, the first in Black Head Surf Club's 90 year history, NSW Premier Mike Baird said: "These attacks are unprecedented, they're extraordinary. They are going to require action."