Turnbull government minister Matthew Canavan has resigned from cabinet and his political career is hanging by a thread after it emerged his mother had signed him up for Italian citizenship without his knowledge over a decade ago.
The resignation is a body blow to the Turnbull government. The Resources and Northern Australia Minister is a close political ally of Deputy Prime Minister Barnaby Joyce and is seen as a rising star within the Nationals.
Senator Canavan announced his resignation from the cabinet on Tuesday evening alongside Attorney-General George Brandis.
He said he would not resign from Parliament because he had not yet been able to obtain definitive legal advice over whether his being granted Italian citizenship, without his signature, knowledge or consent, was valid under Italian law.
If he is forced to quit the Parliament, Senator Canavan will be the third senator to hold dual citizenship who has lost their seat in the last three weeks.
Senator Canavan said his mother had raised with him the possibility he was a dual citizen last week and he had immediately sought legal advice.
"I am a citizen of Italy. I was not born in Italy, I have never been to Italy, and to my knowledge have never set foot in an Italian consulate or embassy," he said.
"In 2006 my mother lodged documents with the Italian consulate in Brisbane to become an Italian citizen. In doing so it would appear she made an application for me to become an Italian citizen as well. I was 25 years old at the time. My mother was born in Australia but was able to obtain Italian citizenship through her parents, who were both born in Italy.
"While I knew my mother had become an Italian citizen, I had no knowledge that I had become an Italian citizen nor had I requested that I become an Italian citizen."
Senator Brandis said it was the government's " preliminary view" that because Senator Canavan's registration as a citizen was obtained without his consent he was not in breach of section 44 of the constitution.
The government will move to refer the matter for determination by the High Court when the Senate convenes next Tuesday.
The Attorney-General revealed the solicitor-general had been dealing with Senator Canavan's situation for some time but did not say how long the government knew there may be an issue.
In a statement, Prime Minister Malcolm Turnbull said Mr Joyce would take on Senator Canavan's responsibilities until his "status is resolved".
Federal MPs are not allowed to serve as dual citizens under section 44 of the constitution.
Greens co-deputies Scott Ludlam and Larissa Waters were forced to resign over the past fortnight after discovering they were dual citizens.
Mr Ludlam resigned on July 14 after being recently told he was a New Zealand dual national. Ms Waters resigned last Tuesday after learning she was a Canadian dual citizen.
At the time, Mr Turnbull said the failure to clarify their citizenship status before standing for election showed "incredible sloppiness".