The couple were on a trip along the east coast of Australia.
A young couple from Switzerland were filming dolphins in the water off a New South Wales beach when a shark attacked them, killing a woman and leaving a man with serious injuries as he tried to fight it off.
About 6.30am, emergency services were called to a beach at Crowdy Bay near Port Macquarie – an unpatrolled beach known to be a shark hotspot.
Bystanders from a nearby campsite provided aid to the victims before paramedics arrived but the woman, believed to be aged in her 20s, died at the scene.
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The woman's boyfriend, a man also aged in his 20s, was airlifted to John Hunter Hospital with serious injuries.
NSW Ambulance yesterday said the man was in a stable condition.
Ambulance Superintendent Joshua Smyth praised a bystander who applied a makeshift tourniquet to the man's leg, saying they "potentially saved his life".
Police are now reviewing GoPro footage the couple recorded which 9news understands shows dolphins in the water, just prior to the attack.
It's believed they were mauled by a three-metre bull shark.
Multiple beaches have been closed, with Surf Life Saving working to secure signage to let beach-goers know ahead of an anticipated hot weekend.
There will be extra surveillance at patrolled beaches on the weekend.
It's not known when the closed beaches will be reopened, though it is believed it could be for at least a few days.
Surf Life Saving NSW chief executive Steven Pearce told 2GB the association was sending up surveillance drones and personnel to support police and the Department of Primary Industries.
"These incidents are horrific for everyone, and unfortunately we've had a few this year," he said.
"This area, it's just so remote, you know, there's no lifeguarding service up there at all."
In a press conference today, NSW Surf Rescue's James Turner said the tragic incident was a reminder of the risks people face when they go swimming on non-patrolled beaches.
"This is in a nice, secluded area where people go to swim, we want them to be aware of the risk in non-patrolled locations," he said.
A report will be prepared for the coroner.
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