House Speaker Tony Smith today issued a writ for the poll, triggered by the resignation of sitting Liberal MP John Alexander over his dual British citizenship.

Alexander, who is part of Malcolm Turnbull’s one-seat majority government, has said he will contest the seat.

He’ll be up against a yet-to-be-named Labor candidate, with federal Opposition Leader Bill Shorten conceding his party will have a tough fight to win Bennelong as the Liberals hold it by more than nine per cent.

He insists, however, Labor will fight hard.

“Labor is behind the eight ball … it is a 10 per cent margin for the Liberals, but we are going to give it every effort because the nation deserves to have a choice about the direction in which the nation is headed,” Shorten told reporters in Canberra today.

He took aim at the scandals plaguing the coalition, including the Liberal National Party’s preference deal with One Nation in the upcoming Queensland election.

“A vote for the Liberal Party in Bennelong is effectively a vote for One Nation on the national stage,” Mr Shorten said.

Labor is currently selecting its candidate for the seat, with Labor MP Tony Burke on Sunday saying the process won’t take long due to time constraints.

Meanwhile, Senators will be set a December 1 deadline to disclose details of their family history and any dual citizenship renunciation, in a bid to clear up any eligibility problems.

A deal was struck between Labor and the Coalition today for a motion to force all senators to publicly disclose the information.

The Senate would then decide if anyone else will be referred to the High Court, which has already disqualified five members of parliament over their dual citizenship in breach of section 44 of the Constitution.

The House of Representatives does not resume sitting until November 27 and is expected to pass a similar resolution.

Leader of the House Christopher Pyne says the agreed process reflects that which the government proposed last week and is a “good outcome”.

However, Labor sources say the shorter deadline and extra information to be disclosed go beyond that proposed by the cabinet.

“All senators will be asked to make a declaration to the Senate by December 1 as to their citizenship status,” Pyne told reporters in Canberra.

“If there is a doubt or if they have a reason in the past, a parent for example with the citizenship of another country, then they have to clear that doubt up by showing how they went about relinquishing that citizenship or what the laws are that show they aren’t entitled to any dual citizenship.”

He called on Shorten to settle on a resolution for the House.

Another victim of the citizenship fiasco, Stephen Parry, who will be referred to the court today, was replaced by Liberal colleague Scott Ryan as Senate President in a secret ballot on Monday.

The Greens, who proposed their own senator Peter Whish-Wilson as president, argued a crossbench president would restore integrity to parliament.

“This government and the way it has handled this citizenship crisis is a disgrace,” Whish-Wilson said.

The Greens may prove to be the key to whether in-doubt Labor MPs are referred to the High Court.

Greens Leader Richard Di Natale confirmed the minor party’s sole MP Adam Bandt would provide the government with the crucial vote it needs in the lower house.

“If the government decides to refer someone, if the opposition decides someone should be referred, we think we should honour that,” Di Natale told the ABC.

Prime Minister Malcolm Turnbull at the weekend vowed to refer any Labor MPs facing dual citizenship questions to the High Court, accusing the Opposition of flouting the law.

That’s brought a “declaration of war” response from Labor.

Pyne says there is “clear evidence” which would justify Labor MPs Justine Keay and Susan Lamb being referred to the High Court.

Labor insists its two MPs took “reasonable steps” to renounce their citizenship before the 2016 election.

It has released legal advice which argues there is no basis Keay, Lamb and South Australian independent MP Rebekah Sharkie are incapable of being MPs under the Constitution.

Each of them lodged a declaration of renunciation of British citizenship with the relevant UK authority before submitting their nomination for election, senior counsel Peter Hanks said.

– AAP