The Greens have advice that the audit should occur through two inquiries, so each house of Parliament can compel members and senators to provide evidence. Greens leader Richard Di Natale wants Australia to take more Rohingya refugees. Credit:AAP Senator Di Natale said each committee could appoint an independent expert, or experts, in immigration law and the constitution, to assess the information. It is understood that the parliamentary committee system already has a budget for expert advice that could be used without needing the government to provide extra funds. "It's pretty straightforward," Senator Di Natale told Fairfax Media, adding the audit should not take long to conduct.

His call follows the resignation of two Greens senators this month, after discovering they were dual citizens and therefore in breach of section 44 of the constitution. Questions have been raised over the status of One Nation senator Malcolm Roberts. It also comes after Nationals senator Matt Canavan resigned from cabinet after revealing his mother had signed him up for Italian citizenship and follows questions over the status of One Nation senator Malcolm Roberts and Liberal MP Julia Banks. Of the 23 MPs who were born overseas, only nine have provided specific documentary evidence they renounced their additional citizenship. There are also other MPs, like Senator Canavan, who may have picked up dual citizenship through their ancestry. The proposed citizenship inquiries would require a majority in both houses before they were set up. Neither the government nor Labor has shown support for a parliamentary audit at this stage.

With the government enjoying only a one-seat majority in the lower house, the eligibility of MPs to sit in Parliament – and the potential triggering of a by-election – also has implications for the Coalition's grip on power. Health Minister Greg Hunt has played down the inquiry idea. "I think the presumption is that everybody is an Australian citizen and if there are individuals or individual cases that are raised where there is a legitimate concern, then it will be up to each individual to clarify that," he told ABC Radio on Friday. Labor leader Bill Shorten has said he had no reason to "disbelieve other people at all". "Most political parties have vetting processes. Certainly the Labor Party does and my national secretariat of the Labor Party, the chief administrators, reassured me on this point with our representatives," he said last week .

Shadow treasurer Chris Bowen said the High Court should be allowed to "get on with the job" "I understand the interest, but we have a robust constitutional institution in Australia. Matt Canavan's case, for example, is very complicated. I think that the best place for it to be sorted through is before our eminent High Court judges," he said on Sunday. Flinders University strategic professor in public policy Adam Graycar said the "most sensible thing" would be for another body, such as the Department of the Prime Minister and Cabinet, to lead the audit. Professor Graycar, who has previously headed up the South Australian cabinet office, said the head of PM&C could lead a small team to assess MPs and then refer any concerns back to the High Court, via the Prime Minister and Parliament. "Having parliamentarians investigate this isn't the best way to do it, because some would be looking to score points, they wouldn't necessarily have the experience or the skill," he said.

With Adam Gartrell