The advice, requested by Labor national secretary Noah Carroll in April, reads: "The resolution of these issues, for the reasons that follow, leads us to the conclusion that it is clearly arguable that Mr Dutton is not eligible to so sit in the 45th Parliament and potentially not eligible to have been chosen for the 45th Parliament. We are of the view that this is the preferable argument." Illustration: Matt Golding Mr Walker represented Barnaby Joyce during the High Court challenge to his eligibility over dual citizenship, and has worked on a similar matter for Labor relating to Nationals MP David Gillespie. "Mr Dutton was incapable of being chosen for the 45th Parliament and is not entitled to continue to sit in the 45th Parliament," the advice reads. "If this matter were referred to the High Court sitting as the Court of Disputed Returns and if our assumptions are correct there is a reasonable prospect that the Court would make its decision in accordance with this conclusion."

But the most outspoken of Mr Dutton's supporters for the Liberal leadership, Tony Abbott, described the emergence of the eligibility questions as "very strange", while the former home affairs minister remained adamant he was not in breach of section 44 of the constitution. "Whether these are dirty tricks from a Labor Party which is desperate not to have Peter Dutton as its opponent or this is just one last throw from a despairing encumbent, I just don’t know," Mr Abbott told 2GB radio. A referral to the Solicitor-General for advice would likely inflame Mr Dutton's backers, and significantly increase instability within the party as a second leadership challenge looms. "Given that today the subject of a member’s eligibility was raised in question time and in media reports, I determined to seek advice from the Solicitor-General on the issues raised," Mr Porter said. "In doing so, I will observe the standard practice that applies to requests from the Attorney-General to the Solicitor-General, which includes not commenting on a matter which is the subject of a request for advice."

Small Business Minister Craig Laundy, who is close to Mr Turnbull, said Mr Dutton should release the legal advice he had obtained about his eligibility "to allay any concerns there may be". "Heaven forbid somewhere down the track, especially if the current situation were to continue and there was to be a change in leadership, this s44 is just like dynamite historically and you’d want to make sure we don’t have collateral damage down the track," Mr Laundy said. The company owned by Peter Dutton's family trust received millions in Education Department funding, placing him in danger of falling foul of the constitution. Credit:Dominic Lorrimer Education Department figures, released under Freedom of Information laws and obtained by Fairfax, show the Camelia Avenue Childcare Centre in Brisbane - operated by the company owned by Mr Dutton's wife Kirilly - received $2.03 million in Commonwealth funding between 2014 and 2018. The same company, RHT Investments (QLD), operates another childcare centre in Bald Hill, Brisbane, which received $3.6 million between 2010 and 2018.

RHT Investments is owned by the RHT Family Trust, of which Mr Dutton and his family are beneficiaries. Loading Mr Dutton's office declined to comment. Sydney University constitutional law professor Anne Twomey had earlier told Fairfax the case was "borderline". “I do think there is a danger for him,” Professor Twomey said.

“I think there is a reasonable case for his disqualification but he also has a reasonable defence." Network Ten on Monday reported a change in the law, which began on July 2, meant childcare centres would now be receiving direct subsidies from the Commonwealth, rather than having the money provided to parents who were then able to spend it on childcare services. Coalition sources maintain the childcare subsidy, even though it is paid directly to a childcare operator, remains in effect a payment to families through the centres. Public accountant Chris Flynn, of Flynn Associates, said the new childcare subsidy, which began in July, was "payable to the childcare centre, but the beneficiary is the Centrelink [account] holder". "It is calculated on the adjustable taxable income and circumstances of the applicant and their partner, not the childcare centre itself," Mr Flynn said.