Charlie Verco has been part of the North Bondi surf club since he was six years old.

By Shannon Corvo and Digby Werthmuller, ABC

An off-duty volunteer lifeguard who pulled a woman from the ocean after she was bitten by a shark has revealed how he helped save her life, while in a state of "panic" himself.

Emergency crews were called to Coogee in Sydney's east just before 11am Saturday, after reports of a "large" shark attack between the lifesaver flags.

NSW Ambulance said the 35-year-old woman suffered "quite massive wounds to her left lower leg and her arms".