NSW man died from suspected heart attack after saving his stepdaughter from a rip

A New South Wales man who dove into rough waters to save his stepdaughter made it back to shore with her before he collapsed and died.

Andrew Wells, 49, and his stepdaughter were at Mystics Beach in Minnamurra on Tuesday when she began struggling in the water.

Mr Wells jumped in to rescue her but after they returned to the beach he collapsed and stopped breathing, News Corp reports.

Paramedics attempted to revive him, however he died at the scene.

Lifeguard Andy Mole said he raced on a jetski from Kiama to assist the Helensburgh man.

"The gentleman went in to get his daughter and both have ended up getting out of difficulty," Mr Mole said.

"He's complained about being out of breath, feeling very nauseous, then he's collapsed and we believe had a massive heart attack."

Mr Wells, originally from Nuneaton in England, married Suzanne Axten-Wells just over a year ago.

Mr Mole said it was important for people to stick to swimming at beaches with lifeguards on duty.

"No flag, no swim ... know your capabilities in the water," he said.