A government citizenship hit-list suggests more than 25 Labor MPs and senators could be under a constitutional cloud because of dual nationality, as Parliament prepares for a new disclosure regime to kick in next week.

The West Australian has obtained a comprehensive spreadsheet prepared by Coalition staff members, which presents research into the heritage of all sitting Labor parliamentarians.

The emergence of the list comes as WA senator Glenn Sterle reveals is seeking confirmation from the British Home Office that he does not hold UK citizenship through his mother.

Senator Sterle said he did not believe he was a dual national through his father, who was born in Yugoslavia, and fled to Australia as a refugee with the rest of his family after the Second World War.

The new citizenship research, which traces the background of MPs through to both sets of grandparents, highlights a number of cases where either proof of renunciation has not been provided, or where issues of potential dual citizenship are yet to be investigated.

Among the MPs listed are two Jewish MPs – Michael Danby and Mark Dreyfus - who the documents suggests may have obtained German citizenship as a result of their refugee fathers, both of whom arrived in Australia in 1939.

Camera Icon WA Labor Senator Glenn Sterle confirmed he was seeking a letter from the British Home Office to clarify his citizenship. Credit: Matthew Poon

Energy Minister Josh Frydenberg has faced similar questions about the potential for him to be a dual Hungarian citizen, given his mother, a Holocaust survivor, arrived to Australia stateless after fleeing Europe following World War II.

The document also suggests that Victorian Labor senator Kim Carr could have inadvertently obtained Israeli citizenship through his marriage, with Israeli citizenship automatically granted to spouses under the Law of Return before 1999. It is unclear whether Senator Carr’s spouse Carole Fabian holds Israeli citizenship, with the document saying the potential split allegiance “has not been looked into.”

Labor claims that it has rigorous internal preselection processes in place to ensure its candidates are not in breach of Section 44 of the Constitution which forbids dual nationality.

However, given the High Court’s hardline application of the constitutional requirement – which has so far seen nine MPs disqualified - speculation is mounting that more MPs from both major parties may yet be ruled ineligible.

Camera Icon Federal Member for Fremantle Josh Wilson is not yet off the hook with regards to the timing of his renounced citizenship. Credit: Simon Santi/The West Australian

Labor MPs Josh Wilson, Susan Lamb and Justine Keay are among the Labor MPs in doubt, given they claim to have renounced their dual citizenship prior to nominating, but did not receive confirmation until after the June 9 deadline.

Mayo MP Rebekha Sharkie, who was elected under the Nick Xenophon Team banner, is also in this category with expectations she will be referred to the High Court following the disclosure process.

Most of the MPs and senators included on the hit-list are those who claim to have renounced their dual nationality, but who are yet to produce evidence.

Under the disclosure regime established by the government, Senators will have until 5pm Friday to produce their citizenship documents and proof of renunciation, while MPs in the House of Representatives have been given until 8pm on December 5.

WA Labor Senator Glenn Sterle confirmed he was seeking a letter from the British Home Office to clarify his citizenship as his mother had been born in England.

But Senator Sterle said he was confident he was in the clear, as he was born in Melbourne in 1960 – well before changes to UK law granted citizenship to children of British-born women overseas.

“I am not entitled to British citizenship,” Senator Sterle said.

“I am only getting (the letter from the Home Office) because you bastards won’t leave me alone.”

Senator Sterle said that as Yugoslavia no longer existed, he could not possibly be a citizen of another country on his father’s side.