Three nippers who raced to the aid of two women who were swept off rocks near Avoca Beach were in the water training for their surf rescue certificate when they found themselves in the middle of a real rescue operation.

The 13-year-old boys, all nippers with the Avoca Beach Surf Life Saving Club, paddled their rescue boards about 500 metres along the beach on Wednesday afternoon to reach the two women, who were believed to be sitting on the rocks just after 4pm when a large wave washed them into the water.

One of the women, aged 27 from Bankstown, drowned at the beach, while a 25-year-old woman from Casula was taken to Gosford Hospital in a critical but stable condition.

The nippers supported the women in the water before they rode with them on the back of jet skis to the beach, where they were assisted by lifeguards and club members.