Malcolm Roberts could be the exception among sitting parliamentarians ensnared in the dual citizen saga in that his election in 2016 may have been invalid, the high court has heard.

Roberts and former senator Scott Ludlam were different to the other three politicians so far referred to the high court – Barnaby Joyce, Larissa Waters and Matt Canavan – because they knew they had been citizens of other countries, the solicitor-general, Stephen Donaghue, told the court on Thursday.

Tony Windsor, the former independent MP and rival to Joyce, has been allowed to join the citizenship case, which chief justice Susan Kiefel has set down hearings in Canberra in October.



Kiefel, at the directions hearing in Brisbane, allowed Windsor to join the case as a “contradictor” after he stood unsuccessfully against Joyce, who belatedly discovered he was a New Zealand citizen.

The chief justice agreed with Donaghue, that the matter of whether up to seven federal parliamentarians who held dual citizenship were valid candidates in the 2016 election was urgent. But proposed hearings in September were pushed back to 10-12 October in Canberra to accommodate legal teams for Canavan and Roberts, who would call experts on foreign citizenship laws.

Donaghue, acting for the attorney-general, George Brandis, said while he would argue Ludlam was disqualified under the Australian constitution, Roberts’ fate would hinge on when his renunciation of British citizenship took effect.

This would likely be resolved once a document Roberts filled out for the British Home Office was before the court, Donaghue said.

Barrister Robert Newlinds, for Roberts, told a directions hearing in Brisbane that Roberts did not concede he was anything but an Australian citizen but that he had emailed British authorities to announce his renunciation of dual citizenship before he nominated for the Senate. Roberts was then sent a form to renounce and had this confirmed after he was elected.

Donaghue said he was aware of a historical document suggesting Roberts was previously a British citizen and, if that was correct, he fell into the category of a person who knew he was a foreign citizen.

Like Ludlam, a New Zealander by birth who also applied for Australian citizenship at the age of 19, the case of Roberts was distinct from others who unwittingly held dual citizenship, Donaghue said.

Canavan’s barrister, David Bennett, said he planned to produce evidence to show a “ridiculous” number of Australians, as much as 50% of the population, would be ineligible to run for parliament if citizenship-by-descent rules of foreign countries were held against his client.



The Liberal National party senator unwittingly became an Italian citizen when he was two years old because of changes to Italian laws that were constitutionally invalid, according to his expert evidence, Bennett said.

Section 44 says any person who is a “citizen of a foreign power” is “incapable of being chosen or of sitting as a senator or a member of the House of Representatives”.

But Donaghue said the attorney general would argue in the case of Joyce, Canavan and probably Waters that none of them knew they were foreign citizens and were not disqualified.

He said the previous case of Sykes v Cleary had prompted the court to find that citizens born in Australia who had not taken “affirmative” action to seek or accept foreign citizenship should not be captured by section 44.

Foreign citizenship laws could not apply where a person “subjectively” did not know they were subject to them, Donaghue said. This was the “clear demarcation line” between the cases before the court, he said.

Donaghue said Canavan and his mother were both born in Australia before 1983, when the Italian government changed laws to retrospectively grant citizenship not just to those with Italian lineage on the father’s side but also the mother’s.

Bennet said the 1983 changes made it “irrelevant” that Canavan’s mother had applied for Italian citizenship when he was an adult on his behalf but without his knowledge.

He had expert advice that the retrospective effect of the Italian laws, in Canavan’s case with the ““slenderest of connections” to Italy, was invalid, Bennett said.

Bennett said he would argue that foreign laws that granted dual “citizenship by descent” to Australians should be ignored.

He said he would apply evidence on foreign rules of citizenship by descent to population figures from the Australian bureau of statistics to show that “possibly in the order of 50%” of people would be ruled out of running for federal parliament.

“That result is so ridiculous” that the interpretation of section 44 had to be “smoothed” to take this into account, Bennett said.

Donaghue said Canavan “retrospectively became an Italian citizen without doing anything”. This was the very kind of scenario that the court in Sykes v Cleary “would find could not be captured” by the constitution, he said.

Donaghue said it was the same case with the Australian-born Joyce, whose father was born in New Zealand before that country’s citizenship was even a formal concept.

Both later unwittingly became New Zealand citizens because of “the operation of foreign law”.

Donaghue said Waters might well be in the same situation because it appeared she never knew about her dual citizenship after she was born in Canada to Australian parents who had no residency rights there.

Waters, like Ludlam, quit the Senate on discovering she was a dual citizen. But if she were found to be a valid candidate, it would open a casual vacancy for which Waters could nominate, having since renounced her Canadian citizenship.

Since their referrals to the court by federal parliament, Joyce’s National party deputy, Fiona Nash, and Senator Nick Xenophon have since declared discoveries they too are dual citizens. The court awaits their referrals next month.

Barrister Ron Merkel, for Windsor, who has applied for permission to conduct cross-examination, said he would carry out research to argue that citizenship by descent was “standard” in international law.

A candidate with an overseas-born parent who signed a form declaring they did not hold dual citizenship upon nomination could then be expected to take reasonable steps that may include obtaining legal advice, Merkel said.

The presence in the case of Merkel for Windsor – who applied for standing 15 minutes before the deadline – raises the prospect he may take a broader role as a “contradictor” who may test the evidence put by legal teams for the other politicians.

Kiefel said the relevance of a candidate’s “subjective” state of mind – whether they knew they were dual citizens – may not lend itself to useful cross-examination.

Newlinds said Roberts could not be ready for hearings in September, as sought by the attorney general, because he sought access to expert advice reportedly held by Brandis on British citizenship rules regarding Nash, and to apply this to the senator’s own circumstances.