Shark policy to bite WA Lib vote: Greens

Western Australia's shark kill policy is becoming an embarrassment that will have political and environment implications for the state, according to the Greens.

Baited drumlines were placed 1km off off Perth beaches on Friday morning, as Premier Colin Barnett continued to defy vitriolic opposition to the policy of killing bull, tiger and great white sharks longer than three metres.

Federal Greens leader Christine Milne will address an opposition rally in Cottesloe on Saturday, and says the policy was proof of a Liberal antipathy towards conservation.

"You have the premier of Western Australia in cahoots with the Abbott government now going out and trying to destroy great white sharks," Ms Milne said.

"It is wrong to institute this cruel policy, which will have by-catch as well.

"(Federal environment minister) Greg Hunt and Tony Abbott do not care about Australia's native plants and animals, and I support anyone taking legal action to prevent what Colin Barnett is doing.

"This is his call, and it is wrong."

With WA facing the prospect of going back to the polls later this year after the senate voting bungle, Greens Senator Scott Ludlam said the policy could cost the Liberal party dearly.

"Sharks have already come back to bite the Liberal party - Premier Barnett's poll numbers have collapsed," Senator Ludlam said.

Earlier, Sir Richard Branson said the policy would backfire, driving away tourism rather than boosting it.

The billionaire entrepreneur made the comment on breakfast radio as the state's Fisheries department was deploying the drum lines.

"I'm sure one of the reasons he (Premier Colin Barnett) did it was because he was thinking it would encourage tourism. It's going to do quite the reverse, I think," Sir Richard told Fairfax radio on Friday.