A groundswell of advice from noted constitutional lawyers suggests Solicitor-General Stephen Donaghue, QC, will likely advise the federal government on Friday that there are doubts over Peter Dutton's right to sit in parliament.

Leading silks Bret Walker, SC, and academics George Williams and Anne Twomey have all said they believe the prime ministerial aspirant has a case to answer over his financial interest in two childcare centres that receives government subsidies.