An 18-year-old tourist from Utah slipped and plunged to his death while apparently taking a selfie at a popular whale-watching spot  in Sydney.

The teenager was with a group of about 15 to 20 friends watching humpback whales at Cape Solander in southern Sydney on Monday afternoon.  One of the group reportedly filmed his horrific fall of up to 60 feet from a rock ledge near a viewing platform. 

Carmelo Pesce, the mayor of the local Sutherland council, said police had seen images of the incident and the teen was “extremely close to the edge of the rock”.

“You’re putting your life at risk and why — for a photo? It’s not that important," Mr Pesce told ABC News.

Emergency crews arrived minutes after a desperate call from one of the friends and found the teenager unconscious in the surf. Lifeguards on jet skis retrieved him and transferred him to an ambulance helicopter but paramedics were unable to save him. 

“We arrived there within seven minutes after being contacted and dropped some green dye into the water which gave us an indication of how fast the direction of the current was, and from that we were able to locate the man just below the surface,” said Stephen Leahy, from Westpac Life Saver Rescue Helicopter.

The incident occurred just six weeks after the death of a man in his 30s who is believed to have fallen as his partner took a photo of him from the same rock ledge. 

Mr Pesce, the mayor, said he would discuss the adequacy of the local warning signs with the local parks authority. 

"I really want to find out exactly where … it happened, was there fencing? Was there any signage there?” he told ABC News. 

“And if we’ve got to look as a community and as a council and a government to spell it out more, we will spell it out more. We will probably need to educate people more."

The coastal clifftop area is a popular spot for watching the migration of whales as they move north towards warmer waters. Passing whales can swim within 220 yards of the shoreline.

Police said the 18-year-old died due to “misadventure”.  

“He was here with a group of friends to go whale watching. They’ve made their way down onto the rock platform at this stage it appears to be misadventure where he’s slipped and fallen over the edge,” said a police spokesman.

“If you are attending this location, those rocks are very slippery so for your safety, stay up on the whale watching platform and please don’t go down on the rocks.”

Various media outlets reported that the teenager was British, though this was not confirmed. It was later confirmed he was Gavin Paul Zimmerman, 19, a Mormon missionary from Utah in the US.