A shark attack victim has been airlifted from a northern NSW beach in a serious but stable condition.

The 29-year-old man from the Central Coast, was surfing in the water off Diamond Head in the Crowdy Bay National Park when he was attacked about 10.45am Friday.

He had lost his right index finger and knuckle on another finger as well as receiving a ‘‘significant’’ bite to his right thigh.

It is believed he was on a paddle board when he was attacked by a bull shark.

An Ambulance Service of NSW spokeswoman said the man was bitten on the thigh and hand.

The Forest Beach man was treated at the scene by ambulance paramedics before being airlifted to Newcastle 's John Hunter Hospital shortly after midday.

The Port News has been told the man, camping at Diamond Head with family and friends, was surfing with friends when a pod of dolphins came through the waves. About 10 minutes later, he was attacked.

The shark hit him three times and it is understood he was injured trying to fend off the animal.

He was assisted from the water by friends.

Surf Life Savers and Lifeguards from Port Macquarie and Taree also were at the beach assisting emergency services.

While other swimmers were quick to leave the water following the attack, the Port News understands it is still open to the public.

Earlier this month a mauled dolphin washed up on nearby North Haven Beach,  about 10kms further north from the scene of today's attack.

Locals then commented about an increase in shark sightings.