His board was snapped in half by the shark.
Paramedics responded to an emergency call at the popluar surf break of Seven Mile Beach about 9.20am.
The 65-year-old man received puncture wounds to his arm and foot and was lucky to escape by swimming to shore.
The man was flown via helicopter to John Hunter hospital and is believed to be in stable condition.
Police said the beach would be closed until further notice.
The attack is the latest in a string of incidents along the NSW coastline.