One man has died, another has incredibly survived, and a boy is missing and feared dead after a boat capsized in rough waves off Sydney’s Northern Beaches.

The call for help came just after 11.30am today when someone on the lighthouse walk spotted a capsized boat at the northern end of Palm Beach.

The tinnie was discovered upside down on rocks, with its engine on fire.

A paramedic was lowered down to the survivor to learn of two more missing in the surf. (Nine)

The survivor was stranded on rocks, bleeding but incredibly lucky to be alive.

A paramedic was lowered down from a helicopter and seen talking to the man as he reveals two others were missing in the water.

“Our hearts go out to the people involved,” Surf Life Saving NSW duty officer Rod McGibbon said.

The victim was winched over wild seas before being transferred to an ambulance.

A surf lifesaver on a jet ski had been the first to respond, pulling a body from the treacherous swell and onto the sand.

The tinnie was discovered upside down on rocks, with its engine on fire. (Nine)

The man was given CPR by paramedics but died at the scene.

“We did have patrols on the beach today, which was fortunate, and they were able to respond very quickly, which is part of the reason we were able to save one of those people,” McGibbon said.

Still missing in the crashing waves is a 14-year-old boy.

NSW Police Acting Inspector Nicole Turner said officers were assisting Surf Life Saving Australia, the Westpac Rescue Helicopter and NSW Ambulance in the search.

The conditions off the coast had been rough today, with a warning issued for large and powerful surf.

Those same conditions have made the search operation more difficult.

The victim was winched over wild seas before being transferred to an ambulance. (Nine)

It’s unclear where the trio had set off from and whether they had seen the warning signs. It did not appear they had been wearing life jackets.

Anyone with information is urged to contact police Northern Beaches police or Crime Stoppers on 1800 333 000.