Shavuot is bittersweet for Marika Weinberger. For the last 68 years, the former president of the Australian Association of Jewish Holocaust Survivors and Descendants has spent the festival mourning.

For it was on Shavuot 1944 that Weinberger and her family arrived at Auschwitz.

That was the last time she saw her mother and two grandmothers before they were marched to the gas chambers. And she never again saw her father, who later perished in Dachau.

Only my sister and I survived. On this Yom Tov, I commemorate them all together,” said the 83-year-old Sydney resident who was one of an estimated 35,000 Holocaust survivors who immigrated to Australia after the war – the largest intake per capita outside of Israel.

But this year Weinberger, who was born in a Hungarian-controlled town called Kosice, has added cause for concern.

Australia’s High Court in Canberra is due to rule whether Karoly (Charles) Zentai, a 90-year-old pensioner alleged to have murdered a Hungarian Jew in 1944, is eligible for extradition.

Like Weinberger, Zentai arrived here by ship, also in 1950, although he disembarked in Western Australia. He has vehemently defended his innocence since he was first arrested in Perth in 2005 after a Simon Wiesenthal Center investigation flushed out information of his whereabouts.

But for the last seven years his controversial case has crawled through multiple state and federal courts, drawn out by legal technicalities.

Now the government, which approved his extradition to Hungary in 2009, has asked the nation’s highest court to finally determine if Zentai – believed to be Australia’s last Nazi war crimes suspect – can be surrendered to Hungarian authorities.

The judges reserved their decision at the end of March; their verdict is expected imminently.

It is alleged that Zentai, then a junior officer in the Hungarian army, and two others tortured and beat 18-year-old Peter Balazs to death for not wearing his mandatory Star of David before dumping his body in the Danube.

But Zentai’s son, Ernie Steiner, told Haaretz from Perth this week that his frail father is innocent.

My father was not in Budapest on November 8, 1944,” he said, referring to the day of the murder. “His unit was moved the day before to a town 70 kilometers west of Budapest.”

He said his father, who still lives alone, would not survive extradition. “His heart specialist, who previously thought he was fit to travel, says it’d be a virtual death sentence,” Steiner said.

But Weinberger says neither age nor frailty is relevant.

My grandmother was also nearly 90 she died at Auschwitz,” she said. “That doesn’t do anything for me when they say he’s an old man. I don’t care; there were lots of old men and women who were taken to the gas chambers.”

Weinberger’s opinion is echoed by Dr Efraim Zuroff, Israel’s chief Nazi hunter, who says it’s “outrageous” that Zentai has eluded justice since the Budapest People’s Court issued a warrant for his arrest in 1948.

The passage of time in no way diminishes the guilt of the killers,” he said. “Old age should not afford protection for people who committed murder.

Don’t look at Zentai and see a relatively old and possibly frail gentleman, but [a man]… who at the height of his physical powers devoted them to the murder of an innocent young boy whose ‘crime’ was being born a Jew.”

Australia has never convicted a Nazi war criminal, even though hundreds found sanctuary there after the war. A special unit set up by the federal government in 1987 investigated 841 suspects. It was shut down in 1992 without a single successful conviction.

It’s hard to be optimistic about a case of a Nazi war criminal in Australia given the county’s terrible record to date,” Dr Zuroff said. “But in this case, the government has acted in the proper manner and perhaps we will finally see a successful result.

Weinberger, however, is not so sanguine. She believes Zentai may suffer the same fate as Konrads Kalejs, who died in Melbourne in 2001 while awaiting a court ruling on his extradition to Latvia for war crimes.

I’m proud to be Australian but this is something that does pain me,” Weinberger said of Australia’s failure to prosecute Nazi war criminals.

I would’ve liked to have lived to the day when at least one would be sent back to answer the brutality and the pain they caused.”

Peter Balazs’s father Dezso, who died in 1970, compiled documents that were handed over to the Wiesenthal Center. In one entry, he wrote: “There is no repercussion that can heal the wound in my heart, as this is a wound that will never heal … They killed him, those whom I will not call wild animals because I do not wish to insult wild animals.”

Mark Aarons, the author of “War Criminals Welcome,” a damning indictment on successive Labor and Liberal governments’ indifference to war criminals finding sanctuary here, wrote in 2009: “Future historians may well conclude that some of the world’s last surviving Nazis died peacefully in Melbourne, Sydney or Perth. This would be a deserved judgment – and a pity.