Accused war criminal Charles Zentai has launched a damages case against the Federal and State governments, with a Supreme Court writ claiming the 91-year-old was wrongfully and unlawfully imprisoned during the Commonwealth's failed bid to approve his extradition to Hungary.
The writ against the Federal Minister for Home Affairs, Federal Attorney-General and WA Department of Corrective Services chief executive claims unspecified damages for Mr Zentai being held in Hakea Prison between October 22 and December 16, 2009.
The Perth grandfather won his protracted legal battle in August when the High Court dismissed an appeal by the Federal Government.
The majority decision by the nation's highest court upheld a decision of the Full Bench of the Federal Court, which ruled that the Home Affairs Minister could not approve Mr Zentai's surrender for an offence that did not exist under Hungarian law at the time it was allegedly committed.
Mr Zentai, who has consistently maintained his innocence, was accused of committing a war crime by murdering an 18-year-old Jewish man in Budapest in 1944.
Mr Zentai surrendered to authorities on October 22, 2009, after losing a Federal Court challenge against his extradition and was taken into custody. The Federal Government approved his extradition the next month.
The then 88-year-old was kept in custody until he was granted bail on December 16. He then launched a fresh Federal Court challenge against his extradition, which culminated in the High Court ruling this year.
Mr Zentai's son Ernie Steiner said the family were seeking legal advice and investigating the prospects of the wrongful imprisonment lawsuit.
Mr Steiner said the family had not made a final decision on the lawsuit, but the writ had to be filed in the Supreme Court within three years to ensure the action remained open to them.
"My father is an innocent man who was wrongfully imprisoned and wrongfully arrested on a couple of occasions," Mr Steiner said.
"It is a devastating thing. It is such a massive injustice. What happened to my father, it could happen to anyone."
The Supreme Court writ alleges that in seeking to have Mr Zentai extradited to Hungary between 2008 and 2012, the Federal Government acted beyond its power.
The writ, which has not yet been served, alleges the governments acted negligently during the extradition proceedings. It claims aggravated and punitive damages.
A Department of Corrective Services spokesman said he could not comment.