Melbourne: Bill Shorten has called on the government to set a stricter test for parliamentarians’ disclosures of foreign citizenship and to require them to produce details of their renunciation of foreign citizenship sooner, by December 1.

After an inconclusive meeting between Malcolm Turnbull and Shorten over the government’s proposed disclosure framework, Shorten raised concerns over the suggested 21-day timeframe and warned a disclosure that asked MPs and senators about their “belief” regarding their citizenship was not a solution “worth the paper it’s written on”.

Turnbull emerged from the Melbourne meeting saying he and the opposition leader had reached an in-principle agreement on the need for disclosure and to give time for both houses to refer potentially ineligible MPs and senators to the high court before the end of the year.

As part of the negotiations with Labor, the government has floated putting on additional sitting time before Christmas to allow the declarations to be made, and considered, with potential referrals to the high court before year’s end.

But Shorten made it clear Labor would oppose additional sitting time. Labor says a resolution should be passed by the House on 27 November, with all MPs making their declarations five days later, so the consequences can be considered within the existing parliamentary sitting timetable.

Shorten warned that MPs and senators must not be “allowed to waltz through” with the excuse they “didn’t know” they were foreign citizens, arguing that would water down the effect of the high court’s citizenship decision that the constitution bans people who are foreign citizens irrespective of their belief.

The government’s proposed disclosure plan would force MPs and senators to produce evidence that they were not foreign citizens at the time of nomination within 21 days of Senate and House of Representatives resolutions.

Labor was quick to express concerns about the 21-day timeframe, arguing parliamentarians should produce documents sooner, given the requirements of the disclosure regime had been announced weeks before the lower house returns on 27 November.

Turnbull said high court referrals may require extra sitting days and the House of Representatives and Senate need to give the issue of eligibility “the consideration that it deserves”.

The citizenship fracas has blown up on multiple fronts this week, with the Liberal MP John Alexander digging in while attempting to clarify his citizenship status with UK authorities, and the spotlight turning on Labor MPs Justine Keay and Susan Lamb over their renunciation of British citizenship.

Turnbull refused to be drawn on Alexander’s case, noting that the MP for Bennelong believes that he is not a dual citizen and saying he would leave it to him to “conduct his own researches” about his eligibility.

Turnbull weighed in on Keay, who admitted in August that her renunciation of British citizenship was not effective until 11 July 2016, after the 9 June nomination deadline.

The prime minister said he understood that Keay had “acknowledged she was a UK citizen at the time she nominated”, which he said “creates an issue”.

Turnbull noted candidates are required to declare they have complied with section 44 of the constitution, which includes a requirement one is not a citizen of another country.

“So that’s going to involve some... considerable legal debate,” he said. “I think the high court’s been very clear on the matter in the recent decision.

“It is a very tough, very literal decision that’s been taken. We have got to comply with it.”

Casting aspersions?

Shorten accused Turnbull of “trying to cast aspersions about the legitimacy of Labor MPs” and said he would not take legal advice from the prime minister because he was confident in the steps Labor MPs had taken.

Constitutional experts have warned that taking steps to renounce before the deadline may not be sufficient to meet the court’s “all steps reasonably required” test in the citizenship seven case.

Under a strict reading of the decision, renunciation must be complete by the deadline unless the foreign law unreasonably refuses to release the person seeking to renounce.

At a doorstop earlier on Wednesday, the Liberal senator Eric Abetz said Keay’s admission put her position in parliament in “serious doubt” and called on her to release her renunciation document to confirm she missed the deadline.

Labor and the Greens both have legal advice that the high court’s decision preserved the defence in Sykes v Cleary that reasonable steps to renounce foreign citizenship will allow a person to qualify — but both have refused to release the advice.

Labor’s defence spokesman, Richard Marles, said the opposition was confident Keay and the Labor MP Susan Lamb were eligible because they had taken “reasonable steps” to renounce their British citizenship before the deadline.

“Justine Keay took all the steps she was required to take prior to nominating before the election to revoke her citizenship and that is born out by the fact that the steps that she took prior to her nominating ultimately resulted in the revocation of her citizenship coming through,” Marles told Sky News.

“That is a very different situation to what we see on the other side, with people basically sitting on their hands and checking a year after election as to whether they have got an issue here.”

Asked at a doorstop in Sydney whether the Coalition would refer Keay and Lamb to the high court, the treasurer, Scott Morrison, said that the government had put forward a disclosure process and would “just run that process and not be distracted in the meantime”.