North Shore Beach shark attack victim Kai McKenzie in serious condition in hospital

A young surfer has lost a leg to a three-metre shark during a mauling at a beach in northern NSW.

Kai McKenzie, 23, was in the surf at North Shore Beach in Port Macquarie when he was attacked about 11am on Tuesday.

WATCH THE VIDEO ABOVE: Young surfer loses leg in horrific shark attack

He saw the shark approach and was able to fight it off but suffered a severed right leg.

Clinging to life, he was able to catch a wave back to the beach.

A retired police officer used his dog’s lead as a tourniquet to stem the bleeding before the victim could be airlifted to hospital.

Authorities say the former officer’s decisive actions “essentially saved (McKenzie’s) life”.

The surfer is currently in a serious but stable condition in Newcastle’s John Hunter Hospital.

The incident comes just months after McKenzie had returned to surfing after recovering from a fractured neck.

“So happy to be back surfing after having a fractured neck,” he posted on Instagram earlier this year.

“Been some real fun times lately.”

A fundraiser has been launched to support McKenzie’s recovery and rehabilitation.

Two white sharks were detected at Port Macquarie on Tuesday morning, and one was caught on a drumline on Saturday.

Smart drumlines and a surf lifesaving drone have been used to track down the shark that attacked McKenzie.

“We will be working ... to try and locate that shark and identify what type of shark that was,” Chief Inspector Stuart Campbell said.

Port Macquarie Hastings ALS Lifeguards shared news of the “serious shark attack” on social media and flagged a day-long beach closure.

“Some members of the public and a fellow surfer were rendering assistance by using makeshift tourniquets,” the post on Facebook read.

“Beaches between North Shore and Lighthouse Beach (Tacking Point) are closed and will remain closed for at least 24 hours.”