The government has proposed it take a 17.3 per cent stake in Australia's most valuable fishery while increasing annual commercial catch limits from 6000 to 8000 tonnes.

The plan will keep back 1350 tonnes for the state to lease to the private sector for additional revenue.

Amid angry reactions from industry, Liberal leader Mike Nahan said the policy was, "like something you'd see in a third world country, nationalising assets."

"We are not an African state," Dr Nahan told reporters.

"Regulate, don't nationalise."

He urged the crossbench to vote down the policy if it reaches the upper house.

Western Rock Lobster Council chief executive Matt Taylor said industry had come up with its own proposal, to be handed to Fisheries Minister Dave Kelly in a few weeks.

Crayfishers had been shocked by the government's scheme, Mr Taylor said, adding it represented government intervention "unprecedented" in primary industries.

"We believe government exists to support industry, not to undermine and then compete with it," he said.

Launching the policy last month, Mr Kelly said the change would "significantly increase" local crayfish supply to the tourism industry and domestic consumers.

Rolled out over the next five years, the Labor package also promises new public sector jobs and $27.5 million in funding for a body corporate and spiny lobster research institute.

Mr Taylor says the industry's proposal includes the same requests but with its own revenue stream and minus the cash injection.

WA's crayfish industry is the most valuable fishery in Australia, becoming the first in the world to be named an ecologically sustainable fishery in 2001.

Quota restrictions by the former Liberal government in 2009 reduced catch allowances to 5500 tonnes, following reports crayfish breeding numbers had fallen to a 40-year low.

Australian Associated Press