One person is dead after a boat with seven people on board capsized in waters north of Wollongong on the NSW South Coast on Sunday.

A major rescue operation involving volunteer surf lifesavers, surfers and paramedics was launched about 10.30am in response to a scene of “carnage” that unfolded near Peggy’s Reef at Bulli.

Surf lifesavers found seven men in the water, four of them unconscious and some trapped under the overturned boat.

Assisted by surfers who paddled out to assist, the volunteers recovered the men and took them into the beach to perform CPR, assisted by members of the public who rotated to help treat the large number of people needing attention.

One of the men could not be revived and died at the scene, NSW Ambulance said, and another three were in cardiac arrest and were rushed to hospital in critical condition.

Steven Pearce, chief executive of Surf Life Saving NSW, said the local club had fortunately been conducting a training exercising so had all its inflatable rescue boats and jetskis ready to launch.

“It’s the quickest response that could ever have occurred for this incident,” Mr Pearce said.

“It was a scene of carnage with debris washed over the entirety of the beach. We had, unfortunately, victims laying unconscious all over the beach.”