Federal Labor leader Bill Shorten has released a letter showing he has renounced his British citizenship.

Key points: After repeated requests, Bill Shorten proves he renounced British citizenship in 2006

After repeated requests, Bill Shorten proves he renounced British citizenship in 2006 Mr Shorten says he did not need to provide proof, but wants the "silly distraction" to end

Mr Shorten says he did not need to provide proof, but wants the "silly distraction" to end High Court to consider eligibility of Nick Xenophon and Fiona Nash, as Ann Sudamaris and Katy Gallagher cleared

Until today Mr Shorten has refused to make the document public, but he has always insisted he had taken all steps necessary to be eligible for Parliament.

Earlier today former prime minister Tony Abbott demanded Mr Shorten either "show it or shut up".

In Question Time Prime Minister Malcolm Turnbull called on Mr Shorten to release proof that he had renounced his UK citizenship.

"All he has to do is produce a piece of paper, that's all he's got to do," Mr Turnbull said.

"What is he trying to cover up. Is it his situation or others?"

Mr Shorten's citizenship was questioned because his father was born in Britain, but after Question Time he tabled a letter showing he had renounced any right to his British citizenship before entering Parliament.

"This silly distraction has to end. The circus has to stop," Mr Shorten said.

"I will not allow the Prime Minister to use a smear about me as a cover about the crisis which engulfs his Government.

"I accept that if I want to be elected PM, there cannot be any doubt about my constitutional eligibility, pushed by the conspiracy theorists like the PM and the Member for Warringah [Tony Abbott].

"I offer this proof to the Parliament today to put an end to baseless allegations, not reward them."

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Mr Shorten told Parliament he did not think other MPs should have to produce documents showing their citizenship status.

But the tit for tat continued as Labor pointed out that Liberal MP Ann Sudmalis said recently that she would release her citizenship documentation when Mr Shorten released his.

Ms Sudmalis has now released a document from the British Home Office showing there is no trace of her ever having acquired British citizenship.

She was born in Australia but her mother was born in the UK and an incoming passenger card from July 1966 listed her as British Australian.

But the "confirmation of the non-acquisition of British Citizenship" form dated last month said their records contained no trace of her acquiring British citizenship.

Sorry, this video has expired The citizenship saga swamping the Government's agenda

More senators referred to High Court

While the arguments about eligibility raged, two more senators were referred to the High Court to decide on their circumstances.

The High Court sitting as the Court of Disputed Returns will consider if NXT party leader Nick Xenophon and Nationals senator Fiona Nash are eligible.

Senator Xenophon's father is from Cyprus, which was a British colony until 1960. It meant he retained a form of British citizenship — and passed it onto his son.

Senator Nash potentially has dual citizenship because her father was born in Scotland.

Labor argued she should stand aside from her ministerial duties until the court decides, in the same way that her Nationals colleague Matt Canavan did.

Barnaby Joyce says he will be in Parliament "until I die". ( ABC News: Matt Roberts )

Other parliamentarians including Deputy Prime Minister Barnaby Joyce have already been referred to the High Court to decide if they were ineligible because of dual citizenship.

Mr Shorten has demanded that Mr Joyce stand aside as Deputy Prime Minister until the High Court rules on his dual citizenship.

The Prime Minister said he was confident the court would find Mr Joyce was validly elected. But Labor disrupted Question Time with demands that Mr Joyce stand aside.

Mr Shorten said Mr Joyce should not be allowed to serve as Acting Prime Minister when Mr Turnbull goes overseas later this week.

"If he does, the entire legitimacy of this Government and this Parliament is at risk," Mr Shorten said.

"And I say to the Prime Minister — do the right thing, do the honest thing, be the strong leader you claim you are, and make the Deputy Prime Minister stand aside."