The Israel branch of the Simon Wiesenthal Centre on Sunday criticised Australia and several other countries for failing to do enough to bring perpetrators of the Holocaust to justice.
The centre's 12th annual report on efforts to hunt down Nazis accuses a raft of nations of failing to prosecute or investigate alleged Nazis.
"The most disappointing result in a specific case during the period under review was the decision by the Australian High Court to reject the extradition request submitted by the Hungarian authorities for Karoly (Charles) Zentai, who was accused of the murder in November 1944 of 18-year-old Peter Balasz," it said.
The Los Angeles-based centre said Zentai allegedly killed the Jewish teenager "whom he caught on a tram without the yellow star required of all Jews," and took part in manhunts for other Jews in Budapest in 1944.
Only the United States scored an "A" on the report; Canada, Germany, Hungary, Italy and Serbia each got a "B".
At the bottom of the table it gave Australia, Austria, Estonia, Latvia, Lithuania, Ukraine, Norway, Sweden and Syria "F" grades.
"Countries like Lithuania, Latvia, Estonia and the Ukraine consistently failed to hold any Holocaust perpetrators accountable, primarily due to a lack of the requisite political will," the report said.
It added that Sweden and Norway "refuse to investigate, let alone prosecute, due to a statute of limitations."
At the top of the centre's list of most-wanted alleged war criminals is Alois Brunner, who is accused of being a key operative for Adolf Eichmann and of responsibility for the deportation of tens of thousands of Jews.
Born in 1912 and last seen in 2001, Brunner lived in Syria for decades, the centre said, but acknowledged the chances of his still being alive were "relatively slim."
The report came as Israel prepared to observe Holocaust Day from sundown on Sunday, with the entire nation coming to a standstill for two minutes of silence on Monday to remember the six million Jews killed during the Holocaust in World War II.