More than 100 people rallied outside a west-end immigration holding centre in Toronto on Sunday to protest last week's massive migrant workers raid.

Demonstrators were hoping their shouts would reach 80 people inside the Rexdale-area building who have been detained and are facing deportation.

"We are here today to fight for their release, to fight against their deportation and to demand that these kinds of enforcement measures do not continue," a protester told a cheering crowd.

On Thursday, about 90 migrant workers were arrested, restrained and bussed to the centre in a series of raids that targeted a number of homes and businesses in Leamington, Danforth and Bradford.

Authorities said the raids are the result of a three-month probe into illegal immigration by the Canadian Border Services Agency.

The detainees are mostly farm and factory workers who advocates say have fallen victim to a failing system. Many of them worked at two Cericola farms in Bradford.

"Employees want these workers," said Stan Raper, a co-ordinator with the United Food and Commercial Workers Canada. "They're not recognized under the immigration point system, so legally they're not allowed to stay."

The Canadian government says the foreign nationals who want to work here must obey Canadian law but protesters argue that they are being treated like criminals instead of assets to the workforce.

"I think we should be angry when anyone in our community is attacked in this way," Macdonald Scott, a lawyer for two of the detainees, told CTV Toronto on Sunday. "All these people are part of our community."

Cericola Farms has not been charged as result of the raids. A company spokesperson said officials will not be commenting on the case for now.

With a report from CTV Toronto's James MacDonald.