Clive Palmer has launched yet another legal claim against Western Australia, this time accusing the government of “unconscionable conduct”.

Mr Palmer on Friday said his company Mineralogy had commenced fresh proceedings in the Federal Court.

He said Mineralogy’s almost $30 billion claim against the state would be amended to reflect additional damages it had suffered.

“The amount of damages is likely to exceed the damages claimed in the arbitration the State had previously agreed to but legislated to terminate,'” Mr Palmer said in a statement.

“Under their unconstitutional Act, we cannot take a dispute to any court. The simple fact is the state of Western Australia does not have the power to control either the Federal or the High Court of Australia.”

It has also emerged Mr Palmer is suing WA Premier Mark McGowan for defamation, having filed paperwork in the NSW registry of the Federal Court.

The premier has variously described Mr Palmer as reckless, selfish and an enemy of the state.

“Mr Palmer is trying to sue me. I won’t take a backward step when it comes to protecting the interests of Western Australia,” Mr McGowan said on Thursday.

“I will always stand up for WA.”

WA’s parliament last week passed extraordinary legislation to amend a 2002 state agreement with Mr Palmer’s Mineralogy company and terminate arbitration between the two parties.

The bill is designed to block Mr Palmer from claiming up to $30 billion in damages from the state.

Mr Palmer secured orders in the Queensland Supreme Court to have the arbitration awards formally registered shortly before the bill was signed into law.

He claimed this meant WA’s “draconian and disgraceful” legislation would now be invalid under the constitution.

The matter returned to the Supreme Court on Wednesday with the WA government arguing it was not notified about the action and the orders should be set aside.

Justice Glenn Martin adjourned the hearing until September 10.

Mr Palmer, through Mineralogy and International Minerals, is pursuing damages over a 2012 decision by the former Liberal government not to assess his proposed Balmoral South iron ore mine in the Pilbara.

The billionaire mining magnate is separately challenging WA’s hard border closures in the High Court.

But it was confirmed he had offered to withdraw the case if officials agreed to move the unrelated arbitration hearings from Perth to Canberra.