The citizenship crisis could claim more government MPs after Attorney-General Christian Porter said they had to prove their possible dual citizenships were renounced.

Labor says this puts Treasurer Scott Morrison, Deputy Prime Minister Michael McCormack, and 12 other Coalition MPs in danger.

Mr Morrison's maternal grandfather was born in New Zealand, while Mr McCormack's was born in Greece in 1896.

The citizenship test in the Constitution has already forced more than a dozen MPs to quit because they were citizens of foreign countries at the election.

"The requirement is that you have to show that you've completed the renunciation process," Mr Porter told reporters in Perth on Friday.

"You need to evidence not merely the start of the renunciation process but its completion. So when people haven't done that, no matter who they are, they need to do so."

Shadow Attorney-General Mark Dreyfus says it sets a new benchmark that goes too far.

"Mr Porter has created a test that many of his own MPs fail. This is a very dangerous path for the government to go down," Mr Dreyfus said.

He says 14 Coalition MPs have not shown evidence of completed renunciations, despite having parents or grandparents born overseas.

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Mr Porter had earlier attacked Labor MP Emma Husar because she had not provided documented proof she had renounced Polish citizenship, which she was entitled to through her paternal grandparents.

Ms Husar says she wrote to the Polish consulate to renounce any entitlement 16 days before her nomination for federal parliament in 2016.

But Mr Porter says Ms Husar had not put on the citizenship register any documented evidence her renouncement was accepted.

Ms Husar told The Australian on Friday she had nothing more to add.

"You have to have something to renounce. You have to have something in order to give it back. I am not a dual citizen," she said.

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Under new rules set to be introduced before upcoming by-elections, candidates have to give their citizenship information to the Australian Electoral Commission.

It will then be made public, but the AEC won't be given the power to adjudicate the eligibility of candidates.

A cross-party committee of MPs has called for a referendum to end the ban on dual citizens entering parliament, but Prime Minister Malcolm Turnbull says there is no time before the next general election.

"Australians expect politicians to get all their paperwork, get all those details together before they nominate," Mr Turnbull told reporters in Queensland on Friday.