The experts, which include Greg Craven, George Williams and the government's security legislation adviser, Brett Walker, believe ministerial discretion should not be more powerful than the courts and that action should only be taken against an individual if there is a court finding against them.

Education Minister Christopher Pyne, a trained lawyer and one of six cabinet minsters to raise serious concerns about the rule of law during a fiery cabinet meeting last month, hinted on Sunday that the laws would be vulnerable to a High Court challenge, saying there was always a risk with such legislation.

Should be litigated in High Court

"We believe that the legislation that we will be introducing in the next fortnight, to strip dual citizens who are foreign fighters of their Australian citizenship, mitigates that risk as far as humanly possible," he told Channel 10. "In the end, that'll be a matter for the High Court to decide, should it be litigated in the High Court."

Mr Abbott could offer no guarantee against a challenge, saying "we are as confident as we can be" the legislation "minimised constitutional risk".

One Coalition source, frustrated at the spectacle of a Liberal government fracturing over national security, said it was inconceivable Mr Dutton and Mr Abbott did not at first seek legal advice.

They have cited similar laws in operation in the United Kingdom but the UK does not have a written Constitution. Mr Dutton has offered to share the decision-making process with the ministers or a panel but that has not resolved the issue of constitutionality.

Shadow immigration minister Richard Marles said Labor's in-principle support for the dual citizen measures still stood but what the lawyers were saying made sense – Labor could not give an informed view until it saw the proposed laws.


"This a dog's breakfast. And what we are seeing is the government really squabbling over what is such an important and profound piece of legislation for our country, like kids in a schoolyard," he said.

Mr Marles demanded the government tell the truth regarding claims six people smugglers were paid $US5000 each to take a boat load of asylum seekers back to Indonesia.

While Foreign Minister Julie Bishop and Mr Dutton originally denied the reports, Mr Dutton is now refusing to confirm or deny. On Friday, Mr Abbott hinted the money had been paid.

"What we do is we stop the boats by hook or by crook because that's what we've got to do," he said.

Mr Marles said Mr Dutton was "either lying or incompetent".