Premier Colin Barnett ruled out further use of drum lines to hook sharks off the state's busiest beaches during the southern summer.
He said his government would now focus on possibly removing "rogue" sharks that "stay in one area for repeated periods".
"While the state government could challenge the (Environmental Protection Authority) decision, all we would find is endless court battles and injunctions," Barnett told ABC radio.
Under the policy, 72 baited hooks attached to floating drums were to be put in place between November and April each year until 2017.
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But the Environmental Protection Authority said yesterday that "there remains a high degree of scientific uncertainty about impacts on the viability of the south-western white shark population".
"At this stage, the available information and evidence does not provide the EPA with a high level of confidence," the agency's chairman Paul Vogel added in a statement.
"In view of these uncertainties, the EPA has adopted a cautious approach by recommending against the proposal."
The Australian Marine Conservation Society said the cull policy "was flawed from the get go, with no clear public safety outcomes but with a heavy environmental cost".
The catch-and-kill policy was introduced as a trial last summer around popular west coast beaches following a spate of fatal attacks.
More than 170 sharks, mostly tiger sharks, were caught during the 13-week season, with 50 of the biggest ones destroyed.
Barnett said sharks that lingered too long in one area needed to be caught and removed, pointing to the killing of a swimmer off a popular beach in the eastern state of New South Wales on Tuesday.
"I'd use the term maybe a rogue shark, a shark that stays in one area for repeated periods, I think we need to catch that shark and remove it.