Emmanuel Macron said "I know" when asked if he thought Scott Morrison lied to him over the dumped $90 billion submarine deal and former prime minister Malcolm Turnbull backed the French President, now Mr Morrison has declared the opposite is true.
The Prime Minister says he "doesn't believe" he has told a lie in public life.
The significant statement, from a grilling on Melbourne local radio station 3AW, comes as trust again emerges as a major election theme.
Asked by host Neil Mitchell if he's ever told a lie in public life, Mr Morrison responded, "I don't believe I have, no."
Just because you ask a question, doesn't mean the person has to tell you the absolute truth.Barnaby Joyce
Mr Morrison's overseas trip to the G20 and COP26 climate summit was somewhat derailed this month after difficult encounters with the French President in the wake of the new AUKUS trilateral grouping and dumping of the $90 billion French submarine contract.
After awkward public encounters, Mr Macron said Mr Morrison had broken the trust between the two countries in severing the Australia-French deal, and when particularly asked by an Australian journalist if he thought the Australian Prime Minister had lied to him, he pointedly said, "I do not think, I know."
Mr Turnbull subsequently said Mr Morrison, his former treasurer, had "a reputation for lying".
Asked on Friday by Mr Mitchell, "How does it feel when a former mate, Malcolm Turnbull, calls you a serial liar?" the Prime Minister tried to shrug it off.
"Look, I mean, it's politics. People take sledges at me all the time ... I've learned in public life over a long period of time to not have a thin skin, to not get bitter," Mr Morrison said.
Deputy Prime Minister Barnaby Joyce backed Mr Morrison, telling reporters on Friday that, "if that's the view he states, then I'll believe him."
Asked whether he had ever told a lie in public life, Mr Joyce said he did not owe the media straight answers to questions about his personal life.
"If you ask me something that's none of your business, then of course I'm going to tell you what you want to hear to get you out of my face," he said.
"Just because you ask a question, doesn't mean the person has to tell you the absolute truth."
The relationship between Australia and France is being tested by the jettisoned subs deal and diplomatic fallout.
In an extraordinary move, a text message from Mr Macron to the Prime Minister was leaked to media in an attempt to address the substance of the French President's accusations.
The French Ambassador to Australia later countered during a National Press Club address that the jettisoned subs deal was a "stab in the back," and accused Mr Morrison of being intentionally deceitful.
The Prime Minister has this week also fronted up to a major U-turn in policy to now support electric vehicles, despite mounting a scare campaign on them at the last election. Mr Morrison has rejected any assessment of his new position as a turnaround as "Labor lies".
He has also raised on morning television what, he said, was a Labor plan at the last election to raise fuel prices to get people to switch to electric vehicles. The Opposition says such a proposition absolutely "never existed."