Senator Canavan quit the cabinet after learning he was an Australian-Italian dual citizen, making him the third senator affected by dual citizenship issues in the last two weeks.
The Nationals Queensland senator claims his mother had acquired Italian citizenship on his behalf, but failed to tell him of it until last week.
Matt Canavan says his mother only told him about his dual citizenship after the recent Green scandal involving their dual citizenship.
"Until last week I had no suspicion that I could possibly be an Italian citizen. In 2006 my mother lodged documents with the Italian consulate in Brisbane to become an Italian citizen. In doing so it would appear that she made an application for me to become an Italian citizen as well. I was 25 years old at the time."
Greens senators Larissa Waters and Scott Ludlam resigned from Federal Parliament when they realised their dual citizenship rendered them ineligible to stand for election.
Scott Ludlam had to step down for failing to renounce his New Zealand citizenship, and Larissa Waters resigned just days later after she also failed to renounce her dual citizenship with Canada.
Deputy Prime Minister Barnaby Joyce has called Senator Canavan a national asset, and is looking for a quick resolution.
"I'm hoping that this thing is resolved as quickly as possible, and after that we can reassess the situation and hopefully get Matt back into his job."
Barnaby Joyce says the former Resources Minister is "competent" and the whole situation is completely surprising.
"This has happened without his consent and he was 25 years old at the time and without his knowledge, he never signed a form. And of course one would presume that if something happens without your knowledge and without your consent then it's probably an invalid process."
Unlike the two Greens senators, Matt Canavan was not born overseas.
"I have become aware that according to the Italian government, I am a citizen of Italy. I was not born in Italy, have never been to Italy, and to my knowledge have never set foot in an Italian consulate or embassy."
Senator Canavan claims he knew his mother became an Italian citizen but had no knowledge he also had become one.
Labor frontbencher Tony Burke has told the ABC that he's never seen a parliament like this one - a year into it and still discovering who's constitutionally allowed to be there and who's not.
"Certainly from the way he's explained it I don't think anyone can be, on the face of it, blaming him for it - if he has never been to Italy and had no way of knowing. Certainly I know in the Labor Party the checks are pretty fierce that are conducted by our national office when anyone nominates and I remember when Malcolm Turnbull was gloating, a little bit viciously at times, about the Greens making some of these errors, I did have a thought of - well be careful about going too hard at this moment in time and now that looks exactly like what's happened to a very senior minister."
Attorney-General George Brandis says the Government will refer the matter to the High Court when Parliament returns.
"We are in the process of taking advice from experts in Italian citizenship law. It is the government's preliminary view that because the registration was obtained without Senator Canavan's knowledge or consent that he is not in breach of Section 44 in the Constitution."
The constitution states:
"Any person under any acknowledgement of allegiance, obedience, or adherence to a foreign power, or is a subject or a citizen or entitled to the rights or privileges of a subject or citizen of a foreign power" ... is "incapable of being chosen or of sitting as a senator or a member of the House of Representatives."
