The possibility of a referendum that would give a minister the power to strip a dual national convicted of serious offences of their Australian citizenship has been flagged by Opposition Leader Peter Dutton.
Similar laws he enacted when a minister were struck out by the High Court as unconstitutional because they allowed politicians to administer criminal punishment rather than the judiciary.
The Commonwealth can apply to a court to strip a dual-national of citizenship if they have committed a serious offence and been sentenced to more than three years prison.
The conduct has to be so serious it demonstrates they "repudiated their allegiance to Australia", according to the Home Affairs Department's explanation of citizenship cessation laws.
The coalition had "no plans to hold a referendum at this stage" and it would be a last resort to enhance national security, shadow attorney-general Michaelia Cash said.
Everything was on the table and a referendum was expensive and took time but "we shouldn't be constrained as governments to protect the Australian people", Nationals Leader David Littleproud said.
Mr Dutton said other options would be looked at but "you can't out-legislate the constitution".
Constitutional and citizenship law expert Helen Irving questioned flow-on effects because it could challenge the separation of powers between the executive and judiciary.
The constitution set out the powers of the courts and judicial independence and tinkering with provisions could open Pandora's box, she said.
"It's very difficult to think through exactly what the ramifications would be," she told AAP.
"You really give the executive the power to rule, in their own opinion, that certain conduct is contrary to allegiance to Australia and there's no clear limit on what might be considered to be appropriate conduct."
Professor Irving pointed to the defeated 1951 referendum when then prime minister Robert Menzies sought the power to ban the Communist Party.
Despite populist appeal, especially during the Cold War, Australians decided such measures threatened civil liberties and were at risk of overreach and this was the risk Mr Dutton faced, she said.
Former immigration deputy secretary Abul Rizvi called it akin to "using an atomic bomb to blow up an ant hill" and pointed to the fact the minister can apply to a court.
"Dutton would cop a thrashing because he would need to argue 'trust me to make decisions, not judges' and people trust judges more than politicians," he told AAP.
"There is zero chance he would take it to a referendum, it's just electioneering."
Prime Minister Anthony Albanese dismissed the idea as "another thought bubble ... that hasn't made it to lunchtime".
"You have Peter Dutton on one TV channel calling for a referendum and Michaelia Cash on another TV channel ruling it out - this has not been thought through," he told reporters in Gladstone.
Mr Dutton previously flagged holding a referendum for tougher citizenship-stripping laws, arguing the High Court had limited such power and the constitution was a barrier.
Law experts have questioned the efficacy of stripping citizenships, arguing it could do more harm than good, including by sending terrorists overseas where there was less ability to track and punish them for offences.
The coalition has been critical of Labor spending $450 million on the voice referendum, saying it divided the country when the money would have been better spent helping struggling Australians.
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