Billionaire Gina Rinehart allegedly asked Liberal National MP Henry Pike if he was considering joining One Nation.
Mr Pike saw the conversation as an attempt to recruit him to the party.
The Coalition has asked the Albanese government if it has concerns about two $500,000 donations to One Nation made by two of Mrs Rinehart's executives.
One Nation's billionaire backer Gina Rinehart allegedly attempted to help recruit a sitting federal Liberal MP after he was invited for lunch at one of her holiday homes.
Henry Pike represents the seat of Bowman for Queensland's Liberal National Party and has previously held fundraisers hosted by Mrs Rinehart.
In January, he arrived at the mining magnate's $34 million Sunshine Coast beach house to find One Nation leader Pauline Hanson, her then chief-of-staff James Ashby and federal MP Barnaby Joyce were staying there.
Coalition sources have told Four Corners that during the lunch, Mrs Rinehart asked Mr Pike if he was thinking of joining One Nation or would ever consider it.
The LNP member saw it as an active attempt by the billionaire to recruit him to the party.
Mr Pike declined to be interviewed by Four Corners.
In a statement, he said: "I have large respect for Mrs Rinehart and all she has achieved.
"But I am, and always will be, a Liberal.
"in the Liberal Party, in our leadership, in our values that shaped modern Australia, and in our ability to do it all again.
"Australia's future is too important for political opportunism."
Mrs Rinehart did not respond to Four Corners' questions about whether she tried to help recruit Mr Pike or other Coalition MPs to One Nation.
Mrs Rinehart is Australia's richest person, with a recent estimated fortune of about $39 billion.
Her support for One Nation has coincided with the party's transformation into a third force in Australian politics, raising questions about her influence.
She has praised Senator Hanson and her policies, while also hosting fundraisers and providing advice to the party.
In an interview with ABC Radio in Perth, Senator Hanson said she had consulted with Mrs Rinehart over various policies.
"My policy on pensioners being able to work unlimited hours and without losing their pension or their health care card came from Mrs Rinehart," she said.
In April, it was announced Mrs Rinehart had gifted a plane worth more than $1.5 million to One Nation, while two of her executives — the former NT chief minister Adam Giles and Ian Plimer — each gave the party $500,000.
Mr Giles also donated a Ford Ranger ute in April.
The largest single donation Professor Plimer had previously disclosed to the Australian Electoral Commission (AEC) was $50,000 to the National Party in 2013-14.
AEC records show Mr Giles had never donated to a political party before under his own name, but his company Adgile Investments had donated $25,000 to the Nationals in 2024 and $27,000 to One Nation in 2025.
The pair's recent $500,000 donations have not yet been published by the AEC, which will publish donation data later in the year.
Four Corners can reveal the Coalition has written to the Albanese government asking if it had concerns about whether Mr Giles and Professor Plimer made the donations on behalf of a third party and whether they would be investigated.
Garth Hamilton, the LNP member for Groom, told Four Corners the donations deserved further scrutiny.
"Those are big donations. I think if you ask that question at the pub, a lot of people would have questions about that," he said.
"Whether it's donations from groups like Climate 200 or whether it's the influence of other businesspeople, there's scrutiny that should always be applied. These ones stand out."
In a statement, the AEC said there had been no official inquiries made into these donations.
"Any donors who have donated for a federal purpose are required to lodge their annual disclosure return for the 2025-26 financial year by 17 November 2026, at which point the AEC considers the information received," a spokesperson said.
Mrs Rinehart did not respond to questions about the donations.
Mr Giles, the chief executive of Hancock Agriculture, said it was his decision to donate.
"I, like many Australians, [am] very worried," he said in a statement to Four Corners.
"I am worried for my country, my state, my industry and my family.