Western Australia state closed beaches and began hunting for a great white shark believed to be responsible for the fifth fatal attack in less than a year, the fisheries department said.
On Saturday the shark took a surfer off an isolated beach at Wedge Island, 160km north of the state capital, Perth, the department's Shark Response Unit spokesman, Tony Cappelluti, said.
The man's remains haven't been recovered.
"We've had officers patrolling the beach since first light today and there's been no further sightings of the shark," Mr Cappelluti said.
Beaches in the area will remain closed until later today, he said.
There are 165 shark species in Australian waters and several, including great white, tiger and bull sharks, are dangerous to humans.
Western Australia, which is spending AUD $14 million (€11.7 million) over the next four years to reduce the risk of attacks, had four fatal shark attacks in a six-month period from last September to last March, according to website sharkattackfile.
Tourism operators in Western Australia, the region at the forefront of the nation's mining boom, attempt to lure domestic and international visitors to the state's 12,000km-long coastline which is studded with pristine beaches.
The tourism industry reaps about AUD $8.1 billion a year and creates 73,300 jobs, according to a Tourism Council document released last year.
The 24-year-old man who died was paddling his surf board when he was taken, the Australian Broadcasting Corporation reported, citing a witness whose jet-ski was also attacked by the shark he described as being five meters long.
The man tried to recover the body before the shark took it, he said.
Western Australia may have to review the policy of protecting great white sharks, said the state's fisheries minister, Norman Moore, according to ABC.
He was cited as saying he was perplexed as to how to counter the shark attacks, which have become a serious problem.
Tourism operators will be banned from feeding the predators to attract them to cage dives, a practice that might change their behaviour in ways posing potential risks to the public, the state government said July 8th.
Studies by Australia's government scientific agency, the Commonwealth Scientific and Industrial Research Organisation, weren't clear about whether feeding great white sharks changed their behaviour in the long term, the government said.
Such risk must be set against any economic benefits, it said.
Bloomberg