Pauline Hanson denies she labelled Liberal MP and former special forces soldier Andrew Hastie a "traitor", while refusing to take down a cartoon at the centre of their dispute.
Mr Hastie claimed in an email to supporters this week Senator Hanson had branded him a traitor, following a cartoon video posted to the One Nation leader's X account.
The nine-minute video, posted on July 23, remains pinned at the top of the senator's X account.
Mr Hastie called on One Nation to delete the cartoon or own up to it in parliament.
The WA-based MP accused the party of politicising the court proceedings of accused war criminal Ben Roberts-Smith and "trashing" his own service record.
"I would say that Pauline Hanson and Barnaby Joyce are lying cowards, and I'll say it again so there's no ambiguity,'' he told News24.
"They are lying cowards.
"And then: On July 23, at the top of her X account, she posted a cartoon ... I'm called a traitor eight times ... when you start calling me a traitor to my own country, then we have a big, big problem."
The One Nation leader rejects his claim, saying she is gobsmacked.
"I'm not calling him a traitor to his country," she told News24 on Wednesday.
"I have not said that. It is a satirical cartoon for Christ's sake.
"Barnaby Joyce was classified as a beetroot. He's now part of the party. Did he jump up and down about it? So stop making a mountain out of molehill."
There has been tension between the SAS veteran and Senator Hanson since he spoke out against Roberts-Smith.
Mr Hastie was subpoenaed to testify in court against Roberts-Smith.
Senator Hanson's closest supporter, billionaire Gina Rinehart, has backed Roberts-Smith, and has named a planned housing complex for veterans in his honour.
Earlier, Senator Hanson told The Nightly newspaper she would define Mr Hastie as "a wanker".
Mr Joyce on Wednesday denied knowledge of the cartoon.
"I dearly hope that nobody is threatening Andrew or his family, and certainly not premising (threats) on anything to do with One Nation,'' he told reporters.
"It's got nothing to do with One Nation."
Mr Hastie said neither Mr Joyce nor Senator Hanson had served "a day in our uniform overseas on operations".
"I stand with a lot of Australians who believe in the rule of law, who believe that Australian soldiers should be held to high standards of battlefield conduct," Mr Hastie said.
