A lawyer for a former Nazi death squad member says the Canadian government has once again stripped the 93-year-old man of his citizenship.

Ronald Poulton says it is the fourth time the government has taken the step against Helmut Oberlander, and the Waterloo, Ont., resident plans to challenge the decision.

Poulton says Oberlander has previously been able to have his citizenship restored three other times.

He says Oberlander is challenging the latest decision in Federal Court and says he expects to be successful again.

Oberlander, born in Ukraine, was a member of the Nazi death squad Ek 10a, which operated behind the German army's front line in the Eastern occupied territories in the Second World War. It was part of a force responsible for killing more than two million people, mostly Jews.

Oberlander served as an interpreter for the squad from 1941 and 1943 and says he never participated in any killings.

The retired real-estate developer did not disclose his wartime experience when he applied to immigrate to Canada, nor did he disclose the information upon entering Canada in 1954 or when seeking citizenship six years later.

Immigration, Refugees and Citizenship Canada says the government is determined to deny safe haven in Canada to war criminals and people believed to have committed or been complicit in war crimes, crimes against humanity or genocide.

"We know the value of Canadian citizenship, and cannot allow anyone to defraud the system or diminish its integrity," it said in a statement when asked about Oberlander's case. "We don't take citizenship revocation lightly, but it is necessary in cases of fraud and serious misrepresentation."

It declined to comment further because the matter is before the courts.

Oberlander, who has been fighting federal attempts to revoke his citizenship since 1995, has said he was conscripted into duty with the Nazis when he was 17 years old and that the penalty for desertion was execution. He later served as an infantryman in the German army.

In July 2016, the Supreme Court of Canada said it would not hear the federal government's appeal of a lower court's decision that told the government to reconsider the case. The decision meant the matter of Oberlander's citizenship was back in the federal cabinet's hands.

Poulton said Oberlander received notification last month of the government's decision to revoke his citizenship.

"(The government) has been wrong three times," Poulton said. "The courts rapped their knuckles each time ... so we are confident we are going to be successful."

He said the case will proceed to a hearing sometime in 2018.

Shimon Koffler Fogel, CEO of the Centre for Israel and Jewish Affairs, applauded the government's most recent decision to revoke Oberlander's citizenship.

Fogel said in a statement that Oberlander has "been exploiting our judicial process to avoid prosecution in Germany."

"There is no statute of limitations for such heinous crimes, and the government deserves credit for its tireless efforts in this case," Fogel said. "This latest development is an important milestone in bringing a measure of justice to his many victims and their families."