A third Turnbull government minister has been caught up in the dual citizenship crisis that has rocked parliament, with Nationals senator Fiona Nash advising she is a British citizen by descent.
Just moments before parliament rose for a two-week break, the deputy Nationals leader told the Senate that she had received preliminary advice from the British Home Office on Monday that she had received dual-citizenship at birth through her Scottish-born father.
But the government waited to make any announcement until it had received further legal advice from Britain clarifying the situation. That came through on Thursday afternoon.
Prime Minister Malcolm Turnbull convened an urgent cabinet meeting just after 6pm, where it was decided, based on advice from the Solicitor-General, that Senator Nash did not have to resign from either the Senate, or lose her cabinet spot as minister for rural health.
.An hour later, the deputy Nationals leader told the Senate that she had become the fourth government member to fall foul of section 44's dual-citizenship rule and would refer herself to the High Court when parliament resumed next month.
"My mother was born in Australia and was an Australian citizen," she said.
"My father was born in Scotland in 1927. I was born in Sydney in 1965.
"My parents divorced when I was eight and my mother raised me.
"I had very little contact with my father throughout his life and he died nine years ago.
"My mother died five years ago. Growing up, my parents always told me that I was not a dual citizen.
"My understanding since early childhood was that in order to be a dual British citizen, I would need to apply for it."
Government MPs have been made to investigate their citizenship status following the shock revelation, sparked by a Fairfax Media investigation, that Deputy Prime Minister Barnaby Joyce had automatically been conferred dual-citizenship at birth, due to his New Zealand-born father.
Senator Nash then investigated her status.
But the government remains convinced that its advice from the Solicitor-General shows both Mr Joyce and Senator Nash will be cleared by the High Court and, therefore, can maintain their cabinet positions.
A third Nationals MP, Queensland senator Matt Canavan, stepped down from cabinet when it was revealed that he held dual-citizenship, after he said his mother signed him up for Italian citizenship, without his knowledge, when he was 25.
Labor has seized on the latest crisis, with Senator Katy Gallagher saying the entire National Party leadership was now facing disqualification from parliament.
"As Senator Nash admitted, she has known since Monday that she was a dual citizen, yet waited until one minute before the Senate rose for a two-week break to inform the parliament," Senator Gallagher said.
"This is simply not good enough.
"Malcolm Turnbull needs to explain why he is holding Mr Joyce and now Senator Nash to a lesser standard than Matt Canavan and not requiring them to stand down."
Mr Joyce, Senator Canavan and One Nation Senator Malcolm Roberts, who has also been referred to the High Court, have had their cases set down for a directions hearing next Thursday.