Cabinet minister Christopher Pyne has threatened there will be tit for tat if Home Affairs Minister Peter Dutton is referred to the High Court.
Mr Pyne warned that if the crossbench bands with Labor to test his colleague's eligibility to sit in parliament, he would attempt to refer independent Kerryn Phelps and Labor MPs Mike Freelander and Tony Zappia.
"It would behove the parliament if they vote to send Peter Dutton to the High Court, that those three MPs will also have to be sent to the High Court," Mr Pyne told ABC radio on Wednesday.
However, the minority coalition government now holds just 74 of 150 lower house seats, and would need to muster several votes to be able to deliver on the threat.
Labor's leader of opposition business, Tony Burke, says the government should take the initiative and test Mr Dutton's eligibility to sit in parliament, especially given a potential legal cloud over some of the minister's past decisions.
"I have continued to call for the government to refer Peter Dutton to the High Court on the grounds that we don't want to take any risk with national security decisions," Mr Burke said.
South Australian independent Rebekha Sharkie said the constitutional questions around Mr Dutton's personal links to two publicly-funded child care centres, and the implications for his eligibility, needed to be investigated.
"I think it's quite clear that Peter Dutton has a case to answer ... I think the best thing Peter Dutton could do would be to refer himself," Ms Sharkie said.
"I don't think the government wants to be seen to be running a protection racket for Peter Dutton, which is what they're sort of alluding to as far as I'm concerned."
Former Liberal frontbencher Julie Bishop says it is up to each MP to satisfy themselves and their electorate that they are eligible to do their job.
"Every member should take their advice. Where there is doubt, then in the past the people have referred themselves or have been referred," she told reporters in Canberra on Wednesday.
"So it's a question for everyone to look at their own eligibility."
