Canada's top court will decide Thursday whether to hear an appeal from a 95-year-old ex-Nazi interpreter fighting to retain his Canadian citizenship — a decision that ultimately could lead to Helmut Oberlander's deportation.

The Waterloo, Ont., man has been engaged in a legal battle with the the federal government since 1995, when the RCMP launched an investigation into his alleged involvement in war crimes. That triggered the process to strip him of his Canadian citizenship, which he has challenged through the courts.

According to the summary of the case filed on the Supreme Court's website, this is the government's fourth attempt to revoke Oberlander's Canadian citizenship on grounds that he "significantly misrepresented his wartime activities" to Canadian immigration officials.

Oberlander's lawyer Ronald Poulton said there is no deportation order against his client so far. Such an order would require a separate proceeding.

"Dragging a 95-year-old who has poor health through such a process, which takes place near the airport in an immigration holding centre, is nothing short of cruel," he said in an email.

"Don't forget, there has never been an allegation that he participated in any kind of crime, let alone war crimes. The only suggestion is that as a 17-year-old, he was forced into being a translator for a German unit engaged in such crimes. The government does not allege that as a translator, he even assisted in the commission of a crime. He was merely present with this unit. This entire proceeding has been grossly unfair."

Old and frail

Poulton said Oberlander is too ill and frail to be interviewed.

Avi Benlolo, CEO of the Friends of Simon Wiesenthal Centre for Holocaust Studies, said that if the Supreme Court decides not to hear Oberlander's appeal, Canada will be one step closer to a deportation that is "long overdue."

"No former member of a Nazi death squad should be given the opportunity to walk free and enjoy the benefits of being a Canadian citizen," he said in a statement to CBC News.

"Regardless of age and whether or not he was directly responsible for the murder of Jewish people in Eastern Europe during the Holocaust, it's time for Oberlander to face justice for his alleged involvement in these murders, just like other former Nazis have over the years.

"Unfortunately, many more former Nazis have gotten away with murder, and we cannot allow that to happen again here in Canada."

According to the Supreme Court summary, there have been four orders to revoke Oberlander's Canadian citizenship. One of those orders was issued in 2017 on the grounds that Oberlander was complicit in crimes against humanity, having made "a voluntary, knowing and significant contribution" to the crimes committed by a Nazi mobile death squad that targeted Jewish people in the former Soviet Union.

Helmut Oberlander has said he was forcibly conscripted by the Nazis when he was 17 years old. (CIJA)

Oberlander is not accused of personally taking part in any executions. He has said he was forced into service and that he never subscribed to Nazi ideology.

Born in 1924 in Ukraine, Oberlander became a German citizen during the Second World War and applied with his wife to enter Canada in 1952. He was admitted as a permanent resident two years later and obtained Canadian citizenship in 1960.

David Matas, senior legal counsel for B'nai Brith Canada, said he expects the Supreme Court to reject his appeal for another hearing.

"He should have been removed long ago. Legally, there was nothing stopping his removal before this Supreme Court decision," he said in a statement.

"The delay is unconscionable. Now that leave will presumably be denied, not a minute should be wasted in effecting his removal. We owe it to the victims and survivors of the Holocaust to see that justice is done in this case before it is too late."

The federal government would not comment on the case because it is still before the court. The Canada Border Services Agency said it cannot comment on specific cases, citing privacy laws.

As for deportation, CBSA spokesperson Rebecca Purdy said the CBSA places the highest priority on removal cases involving national security, organized crime, crimes against humanity and failed refugee claimants.

Once an individual has exhausted all legal appeals, she said, they are expected to leave or be removed. Removal depends in part on foreign governments issuing travel documents.

According to Justice Canada's website, the federal government's position is that "all legal options must be considered when dealing with alleged Second World War criminals and war-time collaborators, including civil action, criminal prosecution and extradition.

"In any given case, the government must take into consideration the facts, nature and quality of the evidence, and Canada's international obligations when selecting a remedy.

"Investigations into Second World War allegations will continue as long as viable routes of investigation remain open. As these cases are finalized, resources used in these investigations are redirected to modern cases."