Statement comes as Turnbull defends his threat to use eligibility question to thwart Dutton’s prime ministerial ambitions

Peter Dutton has revealed that he renounced a financial interest that could have seen him disqualified from parliament before the May election, as he fends off calls for his eligibility to be tested in the high court.

The decision by the home affairs minister to rid himself of the financial interest comes amid fresh revelations about how Malcolm Turnbull threatened to use the constitutional cloud hanging over Dutton to thwart his bid to become prime minister.

Following calls from Labor for the matter to be referred to the high court, Dutton said that the he had given up his interest in the RHT Family Trust before the 18 May election.

The trust had a financial interest in two Brisbane childcare centres which received commonwealth subsidies, potentially putting Dutton in breach of section 44 of the constitution which prevents an MP having “any direct or indirect pecuniary interest with the public service of the commonwealth”.

“To silence those who are politically motivated and continue to raise this; prior to the minister’s nomination at the May election, he formerly renounced any interest in the trust in question,” a spokeswoman for Dutton said.

The minister renounced his interest in the trust despite receiving “unambiguous” legal advice saying he was not in breach of the controversial section, the spokeswoman said.

Despite the advice, reports on Thursday morning revealed that attorney general Christian Porter and Turnbull had clashed amid last year’s Liberal leadership spill over whether General Sir Peter Cosgrove could refuse to appoint Dutton because of the doubts over the home affairs minister’s eligibility to sit in parliament.

It was reported that Turnbull believed Cosgrove should reject Dutton on that basis but that Porter had told him that view was “wrong in law”.

Turnbull defended his view on Twitter on Thursday afternoon: “The discretion to swear in a person as PM is vested in the Governor General. The proposition advanced by Mr Porter that it is none of the GG’s business whether the would be PM is constitutionally eligible is nonsense. The GG is not a constitutional cypher.”

Turnbull said he had sought advice from the solicitor general, Stephen Donaghue, about the constitutional cloud hanging over Dutton’s eligibility, which was made public and given to MPs before they elected Scott Morrison as leader.

“During the week of 24 August 2018 there was advice from leading constitutional lawyers Bret Walker that Dutton was ineligible to sit in the Parliament and thus ineligible to be a Minister, let alone Prime Minister. I ensured we sought the advice of the Solicitor General,” Turnbull said.

“The SG’s advice was delivered on the morning of Friday 24th and duly published. His advice was that ‘the better view’ was that Dutton was eligible but it was ‘impossible to state that position with certainty’ and there was ‘some risk’ the High Court would rule he was ineligible.”

Turnbull’s public defence comes after Porter said he believed he had given “accurate and correct” legal advice to the former leader in saying he could not stop the governor general from appointing Dutton.

But Porter confirmed that the pair had disagreed over the matter.

Bad Blood: five things we learned about the week the Coalition went to war with itself | Katharine Murphy Read more

“The job of the attorney general is to provide advice that he or she considers is accurate and legally correct, and sometimes that advice is not always what people want to hear,” Porter told the Perth radio station 6PR.

“But I have always taken very seriously the role, and the fact that the role requires to give advice that to the best of your legal knowledge and ability you think is accurate and correct, and that is what I have alway tried to do, and that is what I did during the course of that very difficult week.”

When asked if the meeting between the pair during the final days of Turnbull’s leadership had been “tense”, Porter said: “Sometimes meetings in government are not all potpourri and roses, mate, but that’s life.”

According to the two separate reports about the confrontation, Turnbull told Porter he believed he could prevent Cosgrove from appointing Dutton as prime minister because the MP could have a financial conflict under section 44 of the constitution, owing to his wife’s operation of childcare business that received a government subsidy.

Play Video 1:26 'He offered me the deputy leadership': Dutton reveals Turnbull's final move – video

At the time, Turnbull raised doubts about Dutton’s eligibility publicly, warning that if he were unable to sit in parliament he could not validly exercise the powers of a minister.

“This is a very, very significant point,” Turnbull said. “I cannot underline too much how important it is that anyone who seeks to be prime minister of Australia is eligible to be a member of parliament.”

• Sign up to receive the top stories from Guardian Australia every morning

A professor of constitutional law at the University of Sydney, Anne Twomey, said had Turnbull consulted with Cosgrove that would not have been “improper”, but she believed the outgoing leader would not have been able to give “binding” formal advice about a new appointment.

“The outgoing prime minister is no longer responsible to the parliament for that advice and that is why the appointment of a prime minister is regarded as a reserve power,” Twomey told ABC radio.