A man was fatally attacked by a shark at eastern Australia's popular Byron Bay in New South Wales on Tuesday morning despite a beachgoer's brave rescue attempt, police said.

Paul Wilcox, believed to be in his 50s, was bitten on the leg by a shark around 50-65 feet offshore in the waters at Clarkes Beach while swimming on the popular trail from The Pass to Byron Bay, the Associated Press reported. Upon witnessing the attack, beachgoer Mark Hickey, who was paddle boarding in the water, swam immediately to retrieve the severely wounded victim, Police Inspector Bobbie Cullen said.

"A gentleman who was on the beach went out and located the gentleman and pulled him in," Cullen told reporters. "Absolutely it is (an extraordinary act of bravery), and we can only thank him for his efforts."

Hickey, a 52-year-old lawyer on vacation at Byron Bay, told Ten Network television news that he saw the shark and its bloodied victim and swam out to try to rescue the man as the shark attacked again.

"I went out there and, I don't know, I just thought I've got to get this guy in, and that's what I tried to do," Hickey said. According to Ten, Wilcox had apparently bled to death after the shark bit through his wetsuit on his upper right thigh, tearing off much of the leg.

After being pulled out from the water at 11 a.m., Wilcox, who sustained severe wounds to his right leg, was given medical treatment on the beach but did not survive, Cullen said, adding that the leg wounds were being examined to identify the size and species of the shark, BBC News reported.

"A doctor immediately treated the man on the beach, but unfortunately despite clinical intervention including CPR, the man has been pronounced deceased on the beach as a result of his fatal injuries," a spokesman for NSW Ambulance said.

"The victim's family is being notified. Unfortunately his wife was on the beach at the time," Cullen added.

NSW Ambulance paramedic Andrew Chapman said the man was bitten above the knee. "It was a fatal bite with major blood loss. He probably died in the water because there was no blood loss on the beach," he told News Corp Australia.

"It was so horrible we were swimming and got yelled out of the water. It took them 45 minutes to close the beach. I think the whole town is in shock," witness Michelle Campano, who is holidaying in Byron Bay, told Daily Mail Australia.

After the suspected attack, crew of a rescue helicopter spotted what appeared to be a great white shark in the area but lost sight of it, Cullen said. Lifeguards are now attempting to use a helicopter and jet skis to push the animal out to sea.

However, there are no plans to kill the shark, especially with Great Whites being a protected species, Cullen said.

"Byron Bay is a renowned surfing location near Cape Byron, the most easterly point of the Australian mainland, about 800 kilometers (500 miles) north of Sydney," the AP reported. "The last fatal shark attack in Australia was April 3, when a 63-year-old woman was taken by a 3-to-4-meter (10-to-13-foot) shark near the village of Tathra, 340 kilometers (210 miles) south of Sydney."

All Byron Bay beaches would be closed for 24 hours due to the potential danger, Cullen added.