Lawyers for businessman Clive Palmer say WA Premier Mark McGowan used "Churchillian language" when he referred to being in a war with the billionaire.
Mr Palmer is suing Mr McGowan claiming public comments, including labelling him the "enemy of West Australia", made in July 2020 had damaged the Queensland businessman's reputation.
The legal stoush over defamation claims got underway in the Federal Court on Monday.
The premier has lodged a counter-claim that the billionaire defamed him in several interviews.
Lawyers earlier played footage to the court from media conferences Mr McGowan held in July and August 2020 and interviews Mr Palmer gave in August the same year.
Peter Gray SC told the court on Tuesday Mr McGowan regarded the contest with Mr Palmer as at the level of a war, which he distinguished "from a mere battle" by saying: "It's not just a fight, it's not just a stoush, it's not just a battle; it's a war."
He said Mr McGowan used "Churchillian language" when the premier said: "Whatever the outcome of the Federal Court I want every West Australian to understand that whether the commonwealth government supports us or not Western Australia will keep fighting."
One of Mr Palmer's complaints relates to Mr McGowan saying the businessman "wanted to come to Western Australia to promote (anti-malarial drug) hydroxychloroquine to the people of the state as some sort of cure for COVID".
The premier said he was pleased police rejected Mr Palmer's application to enter WA because Mr Palmer "coming to Western Australia to promote a dangerous drug I don't think was a good thing for our state".
Mr Palmer's lawyers have argued Mr McGowan's statements imply the businessman is seeking to harm the people of WA by providing them with a drug he knows is dangerous.
But Mr McGowan's lawyer Clarissa Amato said the comment referred to the drug being dangerous for the treatment of COVID-19, not dangerous generally.
"And that's a very different distinction," she added.
The complaints by Mr McGowan about statements Mr Palmer made relate to circumstances surrounding WA legislation which prevented Mr Palmer and Mineralogy from suing the state for billions of dollars over the Balmoral South iron ore project.
Ms Amato argued Mr Palmer had conveyed that the premier used his position to pass legislation to cover up criminal acts.
Mr Gray said Mr Palmer was referring to the law relating to the project having been drafted in secrecy for months before being passed.
But Ms Amato argued it was an allegation of corruption in the starkest terms.
