A surfer attacked by a shark at a remote beach fought off the 4½-metre ocean predator before catching a wave back to shore on the NSW mid-north coast.

Kai McKenzie, 23, who recently returned to pro-surfing after a neck fracture, is the lucky survivor who escaped the jaws of death at Port Macquarie on Tuesday.

When he reached the sand on the secluded North Shore Beach, a quick-thinking off-duty police officer used his dog’s leash to treat the wounds.

Passersby and the officer used improvised tourniquets to stem the bleeding on McKenzie’s savagely wounded leg.

McKenzie, who remains in a critical but stable condition, has reportedly lost the leg.

NSW Ambulance Service Hastings South acting duty manager Kirran Mowbray said the surfer was recovering at Port Macquarie Base Hospital.

“He actually saw the shark and fought it off and then he’s caught a wave into shore, which is a pretty courageous thing to be able to do,” she said.

Mowbray also confirmed an off-duty officer saw the incident unfold, rushed to the scene and used his dog’s lead as a tourniquet to stem the blood loss before emergency services arrived.

“He essentially saved his life. The only person that saw the shark was the young man himself. He was quite calm. He was able to talk with us. He was completely with it.”

Beachgoers and a surfer were treating McKenzie when lifeguards arrived from nearby Town Beach, Port Macquarie-Hastings lifeguards said on social media.

North Shore Beach, across the river from Port Macquarie in NSW. Photo: Supplied

The sponsored surfer was only recently back in the water after suffering a significant injury.

“So happy to be back surfing after having a fractured neck,” he posted on Instagram in January.

Surfing.com writes that McKenzie is an “up-and-coming” pro surfer and a team rider for Rage, the purple-hued surf grip and hardware brand.

North Shore Beach is isolated and accessible by a dirt road.

There had been several shark sightings to the north of Port Macquarie in preceding days.

A tagged white shark was seen at multiple locations at Sawtell, near Coffs Harbour, on Monday and Tuesday.

Lifesavers evacuated the water at a local beach after the sighting of an unidentified 2½-metre shark on Monday.

BiteMetrix, a website that provides surfers with data on increased risk of shark-human interaction, noted a continued increase in white shark activity in the area in the past week.

-with AAP