An immigration detainee who died in the Toronto East Detention Centre on Monday morning was an adult male, a spokesperson for an Ontario government ministry said Wednesday.

Brent Ross, spokesperson for the Ontario Ministry of Community Safety and Correctional Services in Toronto, said he could not reveal the age or nationality of the man or the circumstances surrounding the death.

The detainee had been arrested by the Canada Border Agency Services (CBSA) and was being held at the provincial correctional centre when he died.

"The facility only holds adult males," Ross said. "There's not a lot I can say."

The CBSA has said the man being detained was in the "care and control" of the Ontario ministry. The agency says it relies on provincial correctional facilities to hold higher-risk detainees in the Greater Toronto Area.

Ross said the Ontario ministry, the coroner, the CBSA and the Toronto police are all investigating the death separately.

If the coroner determines that the death occurred in other than a natural way, an inquest could be held at the discretion of the coroner, he said.

The Toronto Police did not return an email request for information on the death on Wednesday.

At least 13 people have died in custody of Canadian immigration authorities since 2000, according to the University of Toronto Faculty of Law's International Human Rights Program.

'Glaring oversight gap'

Alex Neve, Secretary General of Amnesty International Canada, called for independent oversight.

"It is time for something to be done about the glaring oversight gap when it comes to immigration detention in Canada," he said.

"It is unconscionable that immigration detainees can die in custody and there is no independent agency with a mandate to step in and ensure human rights obligations have been met."

A June 2015 report by the University of Toronto Faculty of Law's International Human Rights Program found that more than 7,000 migrants were detained in Canada in 2013.

About 30 per cent of all immigration detainees were held in a facility intended for a criminal population, while the rest were detained in immigration holding centres in Toronto, Laval, Que. and Vancouver.