Josh Frydenberg has beaten a constitutional challenge to his eligibility to sit in Parliament brought by Melbourne climate activist Michael Staindl, who claims he was unfairly vilified for bringing a legal action against the federal Treasurer.

The Federal Court ruled that Mt Frydenberg's refugee mother did not hold Hungarian citizenship when the "background of catastrophe and anti-Jewish violence and terror" from which she was fleeing was considered, meaning he also did not then hold foreign citizenship.