Federal Treasurer Josh Frydenberg is eligible to sit in parliament.
A voter in his Melbourne seat of Kooyong has been unsuccessful in a claim that the treasurer falls foul of Australia's constitution because he is entitled to Hungarian citizenship through his mother, who fled Europe after World War II.
Michael Staindl's petition arguing Mr Frydenberg was ineligible for re-election last year was rejected by the Federal Court, sitting as the Court of Disputed Returns, on Tuesday.
It's the latest in a string of cases involving MPs with dual citizenship.
Mr Staindl had initially argued Mr Frydenberg's mother Erica Strausz was born a Hungarian citizen and left under a valid Hungarian passport in 1949, which reflected her continuing citizenship.
That citizenship was passed on to Mr Frydenberg at his birth, he claimed.
But it was later accepted by Mr Staindl that the Strausz family left under an emigrant passport, prompting him to claim the "suspension of practical incidents of citizenship", including that of Mr Frydenberg's mother, ended with changes to Hungary's constitution in 1989.
A trio of judges concluded on Tuesday that the legal status of Jewish Hungarians like the Strausz family had to be examined against the "background of catastrophe and anti-Jewish violence and terror" and their desire to leave Hungary for a new life.
Mr Staindl failed to prove Mr Frydenberg ever owed allegiance to Hungary, they found.
Additionally, "the evidence is sufficient to conclude that upon leaving Hungary in 1949 the Strausz family lost or renounced any citizenship of Hungary and were stateless", the court found.
"There is no evidence whatsoever that somehow the political changes nearly two generations later, in 1989, had any effect upon the legal reality as it existed in and after 1949."
Outside court, Mr Staindl said he had been subjected to "unwarranted vilification" for bringing his petition against Mr Frydenberg, "purely for exercising my legal right".
He said he believed section 44 of the Constitution, which prohibits MPs having dual citizenship, needed to be changed.
"I think in our modern world its dual citizenship rule needs to be looked at in a much more enlightened and intelligent way," he said.
"But we also need our leading legislators to follow the law as much or more than anyone else."
