Toronto advocates for migrant workers are criticizing Canada's law that forced 120 laid-off mushroom pickers to leave the country.

The last 18 of the group of mostly female workers were to fly home to Guatemala Tuesday after their employer, Rol-Land Farms in the southwestern Ontario town of Blenheim filed for bankruptcy protection on Dec. 10, the Toronto Sun reported.

Another group mostly from Jamaica and Mexico have already returned home halfway through their work permit because of the layoff, said legal advocate Chris Ramsaroop.

He denounced the federal temporary workers program that allows foreign nationals to work in Canada for two years for a single employer. Workers cannot bring their families and must live in company housing.

"The temporary worker program is a form of indentureship," he told the Sun. "The program is flawed and allows abuse to take place."

While the law allows workers to find a replacement employer approved by the government, Ramsaroop said the process is complicated and lengthy.