Cabinet minister Josh Frydenberg has dismissed as "absurd" speculation he is a dual citizen.
The federal energy minister is the latest senior government figure facing questions over his citizenship, after Senate President Stephen Parry this week bowed out of parliament over his British links.
"When my mother and her sisters and her parents entered Australia after the war their status was 'stateless'," Mr Frydenberg told AAP on Friday.
"It is absurd to think that I could involuntarily acquire citizenship of a foreign country from a stateless mother and grandparents."
Hungary has rules that automatically confer citizenship by descent, following a bid to address the plight of stateless Jews who fled the Holocaust.
Mr Frydenberg's mother was born in Hungary in 1943 and arrived in Australia with her parents when she was seven after spending time in a refugee camp.
He said it was neither rational nor humane that Hungary could purport to make his mother a citizen against her will after rendering her stateless.
Dual citizenship would make him ineligible to be in parliament and threaten the Turnbull government's slim majority.