Prime Minister Tony Abbott says the problem with culling sharks after an attack is "finding the guilty one".
Two surfers have died in shark attacks in northern NSW and Western Australia over the past week, triggering a debate over culling to reduce the risk of further deaths.
Mr Abbott, who is an experienced volunteer surf life saver, said the question of culling was "vexed".
"There is always the issue of getting the `guilty one' so to speak," he told Fairfax Media radio on Monday.
"All of us know there are some risks when we go into the water, but thank God over the years we've managed to take measures to reduce the risks."
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Mr Abbott said if surfers suspected it was the wrong time of day or the wrong place to surf "don't go into the water".
Western Australian Fisheries Minister Troy Buswell has flagged possible talks with the Abbott government to remove the great white shark from federal protected species lists.
Federal Environment Minister Greg Hunt said the commonwealth would be happy to help states' efforts to reduce the risk to humans.
"When people interact in the water they know that this is not their domain and not their territory," he told ABC Radio on Monday.
"But there's clearly been over the last few years, a significant number of tragedies, and we need to understand why, and we need to understand if there is anything that we can do."
