Fifty community groups have joined forces to try and stop the construction of a new refugee detention centre in Laval.

The centre would hold migrants who can't prove their identity and are deemed a danger to the public -- but critics argue it amounts to the cruel treatment of vulnerable people.

The modern, 8,000 square-metre facility would have a play centre for children, and plenty of trees.

“It's not really a solution,” said Mostafa Henaway of the Immigrant Workers’ Centre.

The real problem, he said, isn't the facility itself, but that the whole system is broken. He argues Canada should be more welcoming for migrants.

“A much more cost-effective solution would be to really limit and to have no detention. Migrant refugees, they've broken no laws, so then why do we spend all of these resources to detain them?”

In 2014, a Red Cross investigation found problems at refugee detention centres in Canada, including overcrowding in cells and a lack of support for detained children. It also found that in some cases, when the facility was full, migrants were held in provincial jails alongside violent criminals.

As a result, Ottawa built two new facilities: one in British Columbia and one in Laval. The new detention centre in Laval is slated to open in two years.

Detention centres are necessary when illegal migrants pose a flight risk, are a security threat, or cannot be identified, said Neil Drabkin, former chief of staff to the minister of public safety.

“It is creating havoc in this country because now we have tens of thousands of people waiting for hearings. Many of them are collecting welfare and being put up in hotels. It's unfair to the system, it's unfair to all those waiting in line around the word to come to this country and playing by the rules,” he said.

Imprisonment is not a solution, said Rosalind Wong of Solidarity Across Borders.

“We ourselves can build from the ground up networks of solidarity and support for migrants so they can live here in dignity and in safety here in Montreal,” she said.

“No migrant should be detained,” added Henaway. “No migrant should be criminalized regardless of their status.”