Alleged war criminal Charles Zentai has warded off a final legal bid by the federal government to extradite him to Hungary in connection with the murder of a Jewish teenager in 1944.

The High Court ruling has infuriated and frustrated activists and lawyers who claim that it is further indication that Australia does not take the prosecution of war criminals seriously, while delighting the Zentai family at the same time.

Alleged war criminal ... Charles Zentai. Credit:AP

In its ruling today, the court refused an appeal by the Commonwealth to overturn a decision by the Federal Court that effectively allowed Mr Zentai, now 90, to remain in Australia where he is a citizen.

Mr Zentai told reporters in Perth that he did not know how to react to the decision, such was the stress of the past few days: ''Still the stress, you know, I've been so stressed the last few days in particular, yes. So now I just don't know how I feel.''