OTTAWA -- Ottawa must appeal a court decision that restores citizenship to a former Nazi death-squad member to the country's highest court or it will retain Canada's reputation as a haven for war criminals, Jewish leaders and critics said yesterday.

Keith Landy, national president of the Canadian Jewish Congress, called the Federal Court of Appeal decision "an insult to those who perished in the Holocaust and those who survived."

Earlier this week, the appeal court set aside a federal cabinet order that had revoked Helmut Oberlander's Canadian citizenship.

The unanimous ruling restores the citizenship of Mr. Oberlander, 80, a retired Waterloo, Ont., real estate developer. The federal cabinet stripped him of his citizenship after a court found he lied about serving as a translator for a Nazi death squad when he emigrated to Canada with his wife in 1954. The couple became citizens in 1960.

Mr. Oberlander, a native of Ukraine, was a translator for a wartime Nazi unit called Einsatzkommando 10a, a non-army unit involved in killing Jews.

Critics also want an appeal to the Supreme Court to determine the controversial case of Mr. Oberlander, who has been fighting to stay in Canada since Ottawa revoked his citizenship in 2001.

The federal Justice Department is reviewing the court ruling, said department spokesman Patrick Charette.

Ottawa has 90 days to appeal to the Supreme Court of Canada.