Premier Mark McGowan has revealed the defamation case brought against him by businessman Clive Palmer has cost the state more than $2 million. 

Mr Palmer commenced the case after comments the Premier made at a series of press conferences in 2020, in the early days of the pandemic, before Mr McGowan counter-claimed, saying the action was to protect the state's interests.

Both were found to have defamed each other, with Mr Palmer awarded $5,000 and Mr McGowan awarded $20,000 in damages.

In addition, Mr Palmer has paid $425,700 in costs, after not agreeing to a settlement put forward by lawyers for Mr McGowan.

But WA taxpayers will still be left footing a legal bill worth $2,021,665, something the Premier said he was not happy about.

"That figure may come down because the state is entitled to further costs subject to some further negotiation with Mr Palmer, but that is the net cost at this point in time," he said.

"I didn't want this or seek this, or start the proceedings, but the state and myself could not give in to Mr Palmer in relation to these matters."

Claim and counter-claim

The Queensland mining magnate had told the Federal Court Mr McGowan calling him an "enemy of the state" over his legal challenge to WA's hard border policy brought him into "hatred, ridicule and contempt".

The Premier's counter-claim centred around comments Mr Palmer made in relation to a $30 billion damages claim one of his companies brought against the state, which the WA Parliament passed legislation to head off.

Mr McGowan would not say whether he took personal responsibility for the comments, pointing to the circumstances in which he made them.

The Premier described the period as the "most heated time of my life", with the state defending its hard border in the High Court at the same time as introducing the legislation to end Mr Palmer's $30 billion claim.

He said both "would have had extremely dire consequences for Western Australia in which people actually die in large numbers and the state is then liable for many, many, many billions of dollars".

"We were in a major conflict over the borders. I had not only him [Mr Palmer] trying to bring the border down, I also had the Commonwealth government join him," Mr McGowan said.

"I had the Prime Minister ringing me about it.

"So I had him on my back, I had Clive Palmer suing us, I had the arbitration proceedings for $30 billion, dealing with all of that at once.

"And then, consequent to both of those things, Mr Palmer decided to issue a writ against me because he can, because he's got billions of dollars."

Appropriate for taxpayers to foot bill: Premier

But Mr McGowan said he would "do exactly the same again" in relation to the legislation to protect against the $30 billion claim and measures taken to save lives by closing borders.

"The whole thing, everything here, is regrettable," he said.

It was appropriate for taxpayers to foot the bill, Mr McGowan said, because otherwise politicians could be sued from office.

"I only own a house in Rockingham. He has many billions of dollars," he said.