The federal government would act quickly to refer Labor MPs to the High Court if it believed there were issues surrounding their citizenship.
"If there are Labor MPs with citizenship issues [and] we have enough evidence to refer them to the High Court and Labor does not intend to cooperate, we will refer them without Labor's support," frontbencher Christopher Pyne told Nine Network on Friday.
So far, no Labor MPs have been formally referred to the High Court for breaching the section of the constitution that forbids parliamentarians from holding dual citizenship.
But the Turnbull government could use its slim majority in the lower house to make such referrals when parliament sits later this month.
The coalition has been at the centre of the citizenship debacle, notably losing deputy prime minister Barnaby Joyce who's been forced to contest a by-election for his former NSW seat to re-enter parliament.
But now it's eyeing the bona fides of four Labor backbenchers - Josh Wilson, Susan Lamb, Justine Keay and Madeleine King.
All risk being disqualified from parliament if they can't show they haven't breached the dual citizenship rules.
Mr Pyne criticised Opposition Leader Bill Shorten, who has been negotiating with Prime Minister Malcolm Turnbull to reach an agreement on a proposal for all 226 MPs to provide proof of their Australian citizenship.
Mr Shorten wants a December 1 deadline for MPs to lodge their documents but Mr Turnbull prefers December 7.
"We have said it should be done sooner rather than later," Labor frontbencher Anthony Albanese said.
On Thursday, British-born lower house crossbench MP Rebekha Sharkie, from the NXT party, revealed Mr Turnbull had called her to to suggest she may have to refer herself to the High Court.
