Last August, Bill Shorten gave a “rolled gold guarantee” that none of his MPs would be caught up in the dual citizenship debacle.

“We have a strict vetting process. There is no cloud over any of our people,” he said.

But Mr Shorten has been forced to eat his words after four Labor MPs were forced out of Parliament due to a High Court ruling.

The MPs came unstuck due to the Prime Minister’s requesting November that the Opposition Leader refer all politicians with questions over their status to the High Court.

Mr Shorten responded at the time: “The Labor Party has the strictest processes in place to ensure all candidates are compliant with the Constitution prior to their nomination for election. Therefore, I politely decline your offer.”

He later reiterated: “I am more than satisfied that Labor MPs (are fine) through our vetting process. I am very confident.”

He also attacked Mr Turnbull over the issue, saying the citizenship issue “goes to the legitimacy and integrity of your Government”.

Liberals Stephen Parry and John Alexander and Nationals Barnaby Joyce and Fiona Nash were last year caught out by dual citizenship.

But there are now more Labor MPs forced out of parliament by dual citizenship than coalition members, with an upcoming “Super Saturday” of five simultaneous by-elections seeing the Opposition Leader eating his words.

Three Labor MPs and one independent have signalled they will quit their seats over a High Court ruling on the parliament’s ongoing dual citizenship crisis.

Former ACT senator Katy Gallagher was yesterday ruled ineligible to sit in parliament. She was deemed a citizen of a foreign power — the United Kingdom — when the writs for the 2016 federal election were issued.

Labor MPs Josh Wilson, Justine Keay and Susan Lamb, as well as Centre Alliance MP Rebekha Sharkie, were found to be in the same situation.

All four members plan to recontest their seats in a series of simultaneous by-elections, expected to be held in June.

Labor was already facing a by-election in Perth after frontbencher Tim Hammond resigned for family reasons. The Liberal Party is yet to confirm if it will run there.

All except Josh Wilson’s WA seat of Fremantle are marginal, giving Labor a series of strong challenges ahead.

Ms Lamb’s seat in Longman, in Queensland, is the most vulnerable, held by a tiny margin of 0.8 per cent.

Mr Turnbull has taken a swipe at the MPs for delaying their resignation from parliament..

“They have said they are ineligible, they have acknowledged they are ineligible and they still have not resigned, so they are drawing salaries and using MPs entitlements,” he told ABC Radio this morning.

Mr Shorten faced tough questioning yesterday over his insistence that his MPs would be fine, saying he acted in good faith, following the advice from the party’s lawyers.

“If you get your lawyers, you do take their advice. It’s been the same advice for 20 years,” he told reporters on Wednesday.

“They said our position was sound.”

Yesterday, Leader of the House Christopher Pyne said the Opposition Leader had “proved that he couldn’t be trusted yet again”.

“Last year, Bill Shorten faced a character test over the referral of members of the Labor Party under a cloud to the High Court, and he failed it,” he said.

“He failed it quite spectacularly, and he proved that he couldn’t be trusted yet again.”

Opposition frontbencher Tony Burke argued Labor had tried to refer the MPs as part of a package deal with coalition MPs under a citizenship cloud.

“It’s ended up where it has. We’re now in by-elections and the resignations will be in today for those members and they’re off in their electorates fighting their campaigns,” he told Sky News.

The Super Saturday poll will likely be held next month, with June 16 the earliest possible date.

Mr Turnbull said the polls would “obviously be a very big test” for Labor leader Bill Shorten.

“He asserted that his party’s vetting processes were rolled gold,” he said.

The constitution’s Section 44 (i) states that any person who “is under any acknowledgment of allegiance, obedience, or adherence to a foreign power, or is a subject or a citizen or entitled to the rights or privileges of a subject or a citizen of a foreign power ... shall be incapable of being chosen or of sitting as a senator or a member of the House of Representatives”.

By the High Court’s interpretation, this means anyone must renounce their foreign citizenship in order to run for office.