Treasurer Josh Frydenberg earlier this month.Credit:Alex Ellinghausen
Michael Staindl alleged the Treasurer was disqualified from sitting in federal Parliament under section 44(i) of the Commonwealth Constitution on the basis he was a Hungarian citizen by descent,a claim Mr Frydenberg denied.
Under the Constitution,a person who is"a citizen ... of a foreign power"is ineligible to sit in the Australian Parliament.
The court said"Mr Frydenberg has proved that he was not,and never has been,a citizen of Hungary".
"That conclusion is confirmed by the contemporaneous view of the current government of Hungary,"it said.
The court ordered Mr Staindl to pay Mr Frydenberg's legal costs.
Mr Frydenberg haspreviously said he was not entitled to dual citizenship because his Budapest-born grandparents and their three young daughters,including his mother Erica,were stateless when they fled Hungary's communist regime in 1949. The Strausz family arrived in Australia in 1950.
Mr Frydenberg's mother,born in 1943,became an Australian citizen in 1957,and Mr Frydenberg has never sought Hungarian citizenship.