Chantelle Doyle, 35, surfed off Shelly Beach in Port Macquarie, New South Wales at the time of the attack.
The shark was kicked by her husband before it relaxed its grip and then helped Ms. Doyle to the shore.
With serious injuries to her right leg, she was airlifted to hospital.
Experts cited by the Port Macquarie News claimed that Ms. Doyle had been mauled up to 3 m (10 ft ) in length by a young great white shark.
Surf Life Saving NSW chief executive Steven Pearce thanked the husband-named Mark Rapley by the media-for his timely action.
“This fella paddled over and jumped off his board on to the shark and hit it to get it to release her and then assisted her back into the beach,” he said, quoted by the Sydney Morning Herald. “Pretty full on, really heroic.”
Inspector Andrew Beverley, of Ambulance NSW, said Ms Doyle was given first aid by people on the beach before medicines arrived.
“The bystanders on scene that rendered assistance should be commended. They did an amazing job,” he said.
He added it has been the third significant shark attack in recent months on that stretch of coast.
Ms Doyle had been flown for surgery to Newcastle Hospital and was in a stable condition.