Greens senator Larissa Waters forced out of parliament

The Greens have lost a second senator in less than a week for having dual citizenship, with Larissa Waters forced to resign on Tuesday after she discovered she was still a citizen of Canada.

Like Scott Ludlam, who quit last week when he found out he had dual New Zealand citizenship, the Queensland senator had been co-deputy leader of the Greens.

She said she had left Canada as an 11-month old baby; she’d been born to Australian parents studying and working briefly in Canada.

She had all her life thought that “as a baby I was naturalised to be Australian and only Australian, and my parents told me that I had until age 21 to actively seek Canadian citizenship. At 21, I chose not to seek dual citizenship, and I have never even visited Canada since leaving.”

After Ludlam’s discovery, she sought legal advice, and was “devastated to learn that because of 70-year-old Canadian laws I had been a dual citizen from birth, and that Canadian law changed a week after I was born and required me to have actively renounced Canadian citizenship”, she said.

“I had not renounced since I was unaware that I was a dual citizen. Obviously this is something that I should have sought advice on when I first nominated for the Senate in 2007, and I take full responsibility for this grave mistake and oversight. I am deeply sorry for the impact that it will have,” she said.

Greens leader Richard Di Natale, heaping praise on Waters, said he was “gutted” by her announcement, coming just a few days after Ludlam’s.

He was initiating an overhaul of the party’s processes.

“I have immediately spoken to our two national co-conveners and we are committed to a thorough root-and-branch review so that we strengthen our governance, improve our internal processes and we make sure that this never happens again,” he said.

“I won’t sugarcoat it, we need to make sure that our internal party processes are up to the challenge,” he said. He did not believe there were any other Greens senators in breach of Section 44 of the Constitution, which prohibits a person with dual citizenship being eligible for election to parliament.

The resignation of Waters opens the way for the possible return to the Senate of Andrew Bartlett, who represented the Australian Democrats from 1997 and 2008. He led the Democrats from 2002 to 2004, and was deputy from 2004 and 2008.

On earlier precedents, the High Court would order a countback which would see Bartlett elected.

It is not clear whether he would then remain in the seat or resign so the Greens could fill it again with Waters.

Bartlett said on Facebook that the party’s membership “will be having many conversations over the next few days as we process what has happened and determine what is the best way forward to ensure we remain a strong voice for the essential values the Greens promote”.

Other foreign-born Greens senators hit Twitter to declare their citizenship credentials were in order. Tasmanian senator Nick McKim said he renounced his UK citizenship in 2015, before being nominated by the Tasmanian parliament to the Senate. Fellow Tasmanian Peter Whish-Wilson, born in Singapore, said he did not have dual citizenship.

For good measure, One Nation’s Malcolm Roberts, born in India, and Labor’s Sam Dastyari, born an Iranian citizen, also tweeted they were in compliance with constitutional requirements. Finance Minister Mathias Cormann, who migrated from Belgium, said in a statement that he automatically lost his Belgian citizenship when he became an Australian citizen in 2000.