Federal Resources Minister Matt Canavan has resigned from the frontbench to check the status of his dual Italian-Australian citizenship.
But the government has raised doubts about whether he is in breach of rules forbidding parliamentarians from holding dual nationality.
Senator Canavan announced he was standing down on Tuesday to clarify his citizenship status because his mother is Italian.
"I have become aware that according to the Italian government, I am a citizen of Italy," Senator Canavan told reporters.
In 2006, his mother applied for citizenship and in doing so she made an application for the then 25-year-old as well.
Deputy Prime Minister Barnaby Joyce will be taking over the Resources and Northern Australia portfolio until Senator Canavan's status is resolved.
