The call for Michael Mvogo's release is contained in an "opinion" about Canadian immigration detentions released by the Working Group on Arbitrary Detentions, a copy of which was emailed to Mvogo's lawyer, Macdonald Scott, last week.
Scott and a group of activists from the End Immigration Detention Network, who has been campaigning for Mvogo's release, delivered a copy of the document Thursday to immigration enforcement authorities in Toronto.
"We are hoping for good results that the Canada Border Services Agency will comply with international law and recommend Mr. Mvogo's release in the very near future," Scott said.
Mvogo, 46, was arrested in 2006, a year after he arrived in Canada on a forged American passport under the name of Andrea Walker.
He was dubbed the Man With No Name because authorities were unable to confirm his identity until early 2011, when Mvogo revealed his name and said he was a citizen of the African country of Cameroon. Efforts to deport him have been unsuccessful.
In its opinion, the Geneva-based UN group also called on the Canadian government to compensate Mvogo, saying the authorities have failed to demonstrate that his detention is necessary and proportionate.
"The inability of a state party to carry out the expulsion of an individual does not justify detention beyond the shortest period of time or where there are alternatives to detention, and under no circumstances indefinite detention," the document said.
Scott said that the rationale behind the group's opinion applies to over 60 long-term detention cases in this country.
A spokesman for Public Safety Minister Steven Blaney did not comment on Mvogo's case, but rejected the UN group's criticism.
"It is time the UN and its committees turn full attention to the true humanitarian crises of the world rather than spending time and resources scrutinizing modern, rights-based democracies," Jason Tamming said in an email to The Canadian Press.
Canada should release Mvogo, compensate him and release any immigrants detained for more than 90 days, said Scott.
"That should be followed by a thorough overhaul of the detention review process and an end to maximum security incarceration of migrants."
Tamming noted that Canada has a fair and generous immigration system that has consistently welcomed over 250,000 legal immigrants each year since 2006.
"It is reasonable that those who do not play by the rules and seek to take advantage of our generosity be detained and asked to leave," he said.