The man in his 50s sustained serious upper thigh injuries while surfing Tuesday morning, NSW Police said.
Emergency services were called at Tuncurry Beach, Forster, about 300 kilometers (186 miles) north of Sydney, at around 11:20 a.m. local time (9:20 p.m. ET), police said.
The man actually spotted the shark early on and tried to warn his friends, Police Commissioner Christopher Schilt told reporters at the scene.
CNN affiliate 9News reported that the man’s three friends swam towards him and dragged him to shore. He went into cardiac arrest due to blood loss, 9News added.
Onlookers and paramedics worked together to save the victim, NSW Ambulance said in a tweet on Tuesday.
Officers from the Manning Great Lakes Police District attempted to resuscitate him, but he died at the scene, the force added.
The shark in question is believed to be around 4.5 meters (almost 15 feet) long, said the Department of Primary Industries (DPI) of NSW, a government agency responsible for fisheries and agriculture.
Along with the police, the DPI is monitoring the area with drones and around 20 kilometers (12.4 miles) of beach has been closed to the public for at least 24 hours.
Eight fatal shark attacks, including two in New South Wales, were recorded in Australia in 2020, according to the Taronga Conservation Society.