The lawyer for a former Somali child refugee says his client is "extremely disappointed" a Federal Court judge has refused to temporarily halt deportation proceedings against him.

Abdoul Abdi, who never got Canadian citizenship while growing up in foster care in Nova Scotia, was detained by the Canada Border Services Agency after serving five years in prison for multiple offences, including aggravated assault.

In a decision released Friday, Justice Keith Boswell rejected his request to press pause on his deportation proceedings while he pursues a constitutional challenge, saying there were no exceptional circumstances warranting inference by the Federal Court.

"He's extremely disappointed and upset by the decision," said Abdi's lawyer, Benjamin Perryman.

"I would have liked to have seen some consideration of the harm that Mr. Abdi will experience when he's ordered deported and I would have liked to hear some consideration of the fact he will lose important rights before there can be any consideration of his constitutional issues."

Abdi, who has been living in a Toronto halfway house since his release in January from immigration detention, had asked the Federal Court to temporarily suspend his deportation hearing, scheduled for March 7 in Toronto.

Perryman said he disagrees with the judge's ruling. He said Prime Minister Justin Trudeau and Immigration Minister Ahmed Hussen "both say the child-welfare system failed Mr. Abdi, I think it's exceptional we're still proceeding to a deportation hearing."

Perryman said the federal government has refused to pause the deportation hearing, but still has the power to do so. He said Abdi could also make another postponement request to the Immigration and Refugee Board.

Abdi will be at the deportation hearing with a Toronto-based lawyer.

But if a deportation hearing proceeds, Perryman said Abdi will be ordered deported. He said the Immigration and Refugee Board of Canada cannot consider human rights law or the reasons why Abdi did not become a Canadian citizen.

Perryman said Abdi is focusing on work. He was recently hired to be part of a research project that examines youth who have contact with both the child-welfare system and the criminal justice system.

Should the deportation order move forward, Perryman said Abdi could lose his right to work and his right to health care in Canada.