Premier Colin Barnett says companies are reviewing their investment decisions in the state in light of the federal government's proposed new super tax on miners.
Mr Barnett has joined mining companies in criticising the tax, saying it would jeopardise future projects in Australia, cost jobs and pose a real threat to the industry.
Today he said many companies were rethinking their future in WA because of the tax.
"I have been struck over the last 24 hours by the numbers of both larger and smaller companies that are clearly reviewing investment decisions," Mr Barnett told ABC Radio.
"It's cast a cloud, a shadow over the optimism in Western Australia."
The federal government on Sunday proposed a 40 pr cent tax on mining companies' super profits, which will be used to pay for a cut in company tax and a range of superannuation measures.
The proposal has caused howls of protest from the mining sector and lobby groups.
This afternoon in parliament, Mr Barnett said he would ask the fedral government to reconsider the tax proposal, adding that the policy had been "hopelessly designed".
"This is a hopelessly designed tax arrangement and it should be opposed," Mr Barnett said.
"I would ask the federal government to reconsider this whole proposal. This will damage mining in this state ... it will cost current and future jobs.
"The structure is nonsensical."
Mr Barnett comments come as Prime Minister Kevin Rudd lands in Perth to promote the proposed tax reforms.
Federal Resources Minister Martin Ferguson this morning met with Chamber of Commerce and Industry WA chief executive James Pearson to listen to concerns that the group's members had expressed with regards to the new tax.
"This is a tax which the industry reckons will have a significant effect, potentially, on its ability to compete internationally," Mr Pearson told reporters today.
"The industry depends on domestic and international investment to grow, we must make sure that we don't do anything that would harm investment in the area.
"I'm confident that the minister heard the message I gave to him today and I asked him to convey that to his colleagues in Canberra."
