A spokesman for Mr Taylor said the minister's interest in Derwent Executive ended by contract with its managing director Ben Derwent in January 2016, six months before he nominated for the federal election.

"Mr Taylor has had no relevant interest in the company since that time."

Mr Derwent has supported the claim.

However, the minister did not update his register of interests until March 21 the following year, which AAP understands was due to lateness on Mr Taylor's behalf.

Section 44 of the constitution disqualifies anyone who has a "direct or indirect pecuniary interest" in any agreement with the Commonwealth.

The Australian reports Derwent Executive had a contract with an independent statutory body that receives state and federal government funding, raising questions about whether it was a contract with the public service.

But University of Sydney constitutional lawyer Anne Twomey says "there's a step of remoteness" as the independent statutory body concerned was not a government department.

Labor had earlier demanded the minister come clean about his eligibility to sit in parliament.

"We cannot have yet another Morrison government minister whose eligibility to serve in the parliament and eligibility to remain a minister remains in doubt," Shadow attorney-general Mark Dreyfus told reporters in Melbourne on Tuesday.

The opposition is also continuing to pressure Home Affairs Minister Peter Dutton over his family's interests in two childcare centres which received commonwealth subsidies.

Mr Dutton has consistently dismissed questions over his eligibility, citing legal advice which he says puts him in the clear.

Australian Associated Press