The Jewish human rights group Simon Wiesenthal Centre is calling on the Federal Government to appeal yesterday's court ruling, which overturned an extradition order for accused war criminal Charles Zentai.

The Perth man won a lengthy battle against extradition to Hungary, where he is wanted for questioning over the murder of a Jewish teenager during World War II.

Home Affairs Minister Brendan O'Connor approved the 88-year-old's extradition late last year, but now a Federal Court judge has ruled that Mr O'Connor received bad advice.

Justice McKerracher ruled it would be oppressive to extradite the 88-year-old, given his age and ill health.

Moreover, he said no action had been taken against Mr Zentai until 2005, more than 60 years after the alleged murder.

He said Mr O'Connor was advised that Mr Zentai was accused when he was only under suspicion.

He also referred to the unreliability of the original allegations, and the fact that there was no such thing as a war crime in Hungarian law in 1944.

Defence Counsel Malcolm McCusker QC says Mr Zentai was not an eligible person as defined by the Act.

"That's a very serious finding; it means that it's not just a matter of sending it back to the Minister; it's unlawful," he said.

Mr Zentai - who has always proclaimed his innocence - could not believe it when he heard the decision.

"Well, it's just an amazing feeling. It's really hard ... I can't describe," he said.

"When I heard it, I didn't want to believe my ears. I didn't dare to expect it."

Mr Zentai's family says the lengthy legal battle has cost them around $200,000 and they have not ruled out seeking compensation.

His son Ernie Steiner says the Australian Government made several errors in the way it handled his father's case.

"I'm very critical of the Attorney-General's department," he said.

"I think they advised the Minister poorly. They were meant to look at detail; they got details wrong. And I think the interests of an Australian citizen were not adequately represented.

"My father has undergone a huge injustice and perhaps the issue of compensation would be appropriate."

Outrage and disappointment

But the Simon Wiesenthal Centre says it will not give up on the case.

The centre's Dr Efraim Zuroff took the original allegations to the Hungarian authorities, which led to an international arrest warrant being issued in 2005.

Dr Zuroff says he is outraged and disappointed by the Federal Court's "absurd" decision.

"I would say it's deep disappointment and frustration. This is a very sad day for Australia, I have to say. It's sad day for Australia; it's a sad day for Australian justice," he said.

"I think it's absolutely absurd, the whole issue of his age is totally irrelevant because there's never been a single country in the world, including Australia, which has ever limited prosecution based on age."

Dr Zuroff says Australia has failed in terms of Nazi war criminals and the centre will do what it can to push the case forward.

"It has to be clear, Australia was not asked to determine his innocence or his guilt, that is for a court in Hungary to do, and the fact that many years passed without him being brought to justice is totally irrelevant, the passage of time in no way diminishes the guilt of the killers," he said.

Mr O'Connor has issued a statement saying he is considering the judgement handed down by the Federal Court.

He says it is inappropriate for him to comment on the decision because the case may come before him again.

But Mr Zentai's son has urged the Federal Government not to appeal against the decision.

"We just want to put it behind us and let my dad have his remaining years in peace and surrounded by family," he said.

abc.net.au