Federal Labor has seized on new evidence suggesting a financial agreement between the Commonwealth and one of Peter Dutton’s childcare centres.

Any attempt by Labor to have Mr Dutton’s case taken to the High Court to assess his eligibility to sit in parliament would need to support of Coalition as well as Labor MPs.

Mr Dutton has insisted that he is not in breach of section 44(v) of Australia’s constitution, which prohibits politicians getting a financial benefit from the Commonwealth.

The Home Affairs Minister has ownership stakes in two childcare centres in Brisbane which receive Commonwealth subsidies for their services.

Mr Dutton has obtained legal counsel which alleges that the subsidies did not put him in breach of the constitution because they were part of a broad policy and not an individual agreement.

However, new documents have revealed an agreement between one of the Brisbane centres and the Commonwealth for the funding of a specialist teacher for an autistic child.

Mark Dreyfus, the Shadow Attorney-General, said that the new information added some weight to Labor’s demands for Mr Dutton’s eligibility to be assessed.

He also denied that the symbolic merit of the agreement, assisting a disabled child, should be considered in the debate. He said that “the prohibition in the constitution is absolutely clear”.

The issue of Peter Dutton’s parliamentary eligibility was urgently raised during the Liberal leadership spill last month, in which Dutton was a contender to become Prime Minister.

The nation’s top lawyer, Solicitor-General Stephen Donaghue, said that the subsidy scheme did not render Mr Dutton ineligible but that he could not be certain as he did not have all the facts in front of him.