Last year, temporary foreign workers filed at least 250 complaints across Canada about employers mistreating them, braving a system that critics say is designed to work against them.

But that number, obtained by CBC News from individual provinces, only represents a small slice of a potentially larger problem.

Only three provinces — Alberta, Saskatchewan and Newfoundland and Labrador — routinely track complaints made by migrant workers. That makes it hard to know the true extent of workplace difficulties that these employees face across the country.

"It's an enormous problem," says Chris Ramsaroop, an organizer for the Ontario- and B.C.-based non-profit group Justicia for Migrant Workers. "The fact that they are not tracking vulnerable workers in general is a concern. It shows a lack of enforcement."

A couple of provinces are taking a different approach — auditing workplaces that employ temporary foreign workers instead of relying on the workers themselves, who often face language barriers and fear jeopardizing their jobs, to come forward. But the Canadian system is still largely complaint-based.

If most provinces are not tracking complaints, "that just goes to show the extent to which the existing enforcement mechanism is not serving those workers well," says Fay Faraday, a Toronto-based human rights lawyer and author who has extensively researched migrant workers in Canada.

Nearly all the 250 or so complaints on record last year were in Alberta, which has one of the largest populations of migrant workers, and has meticulously tracked complaints for the past seven years.

In 2013-2014, it saw 242 workplace complaints from migrant workers, just a few less than its yearly average of 245. Wages and overtime issues topped the list.

Faraday suggests the reason for Alberta's scrutiny may be because Ottawa's Temporary Foreign Worker Program has "been in the spotlight in Alberta for much longer." In the 2000s, local campaigns raised awareness about the difficulties faced by these temporary employees.

Newfoundland and Labrador — which has one of the smallest TFW populations, but is facing exploding numbers — logged one complaint in the last fiscal year. That's down from two in the year prior.

Saskatchewan investigated seven complaints by temporary foreign workers in the same period, the ministry of economy said.

Searching for red flags

Prince Edward Island is the only other province able to quantify workplace complaints by temporary foreign workers in recent years.

However, that's because it only had one that stood out: the case saw a seafood plant forced to pay $150,000 to 45 Thai workers, who were reimbursed for the plant wrongly withholding pay and unjustly firing some of the employees.

"This information is available only because it is memorable due to the number of appellants, the amount of the award, and the time and effort that was put into collecting the monies," said government spokesman Wayne MacKinnon. "The branch does not keep stats on TFWs as PEI's employment statements apply to all employees equally."

The federal TFW program has been in the news repeatedly these past few months because of a series of controversies that the CBC and other media outlets have reported.

But most provinces say they don't know how many foreign workers have launched employment-standards complaints because they don't record the type of complainant based on immigration status (or on race and gender).

That lack of information may affect what gets passed from the provinces — responsible for enforcing workplace rules —  to the federal government, which issues the approvals for companies to hire temporary workers from abroad.

"You've got the federal immigration sphere working quite separately from provincial enforcement agencies, and having those silos is not productive for actually ensuring compliance on the ground," said Faraday.

Ontario, home to a third of Canada's temporary foreign workers, is among provinces that don't track claims by type of claimant.

"As a result, information about complaints from temporary foreign workers cannot be passed on to the federal government," said William Lin, spokesman for Ontario's ministry of labour.

Some provinces, like Nova Scotia, which doesn't specifically track foreign worker complaints, say they do alert the federal government if there is an investigation.

Nova Scotia looks for red flags in its investigations, such as an employer taking a worker's passport or someone being charged a fee for coming to Canada, issues typical of temporary foreign worker problems.

The province doesn't share personal information with the federal government without consent, and usually directs temporary foreign workers to contact the federal government themselves, says N.S. spokeswoman Chrissy Matheson.

Four companies blacklisted

None of the provinces disclosed how often they've notified the federal government about potential problem employers, a first step that might lead to having the approval to hire foreign workers revoked, nor could the federal government provide that number.

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Employment Minister Jason Kenney is expected to announce changes to the temporary foreign worker program in the coming weeks. The program's faced intense scrutiny in recent months. (Canadian Press)

The federal government also reviews employer compliance, but refuses to disclose how many reviews it has done. The reviews have "increased every year for the past several years," Employment and Social Development Canada spokesman Jordan Sinclair wrote in an email.

On April 7, after a spate of temporary foreign worker stories in the media led to questions in Parliament, ESDC posted an online employer "blacklist" for the first time. Since then, the list's featured four employers whose approvals to hire TFWs have been revoked or suspended.

Still, ESDC only oversees a portion of companies hiring temporary foreign workers. Citizenship and Immigration, which oversees all work permits granted to temporary workers, has hosted its own blacklist since 2011.

However, that list is currently blank and the department has not responded to requests about how many companies it's featured in the past. Companies appear on the blacklist for two years, and must still be actively seeking new workers to be included.

Barriers to filing complaints

The federal government has repeatedly noted over the years that temporary foreign workers have the same rights and protections as Canadian workers under federal and provincial standards and labour laws. That includes the ability to file complaints if they face mistreatment in the workplace.

However, critics argue that migrant workers are far less likely to come forward because they are tied to a single employer through their work permit.

"It is very, very difficult to file a complaint," said Faraday. "The power imbalance is just too great."

They also face barriers such as language and lack of understanding of their rights in Canada.

To help remedy that, the federal government does work with the province to give information to both employers and workers about provincial labour standards.

Four provinces — B.C., Alberta, Manitoba and Saskatchewan — also have specific agreements in place with the federal government to share information that will help them protect temporary foreign workers.

But some provinces without such pacts complain that they don't know which companies employ TFWs in their jurisdictions, making it difficult to proactively enforce their labour laws.

"Most provinces have no idea where temporary foreign workers are, and I think that's also a big problem," notes Ramsaroop.

Proactive auditing

Ontario has been calling on the federal government for years to share information that would help it identify employers of TFWs in the province. The two levels of government are currently in negotiations.

Knowing which employers are hiring temporary workers from abroad has helped Manitoba design its own system for protecting the vulnerable employees.

There, a provincial registry of employers allows the province to monitor employers who use temporary foreign workers by listing how many they employ and where they are located.

The program, which began in 2009, sends special investigators to audit workplaces that employ vulnerable workers, like those here on the TFW program.

Each year, its investigators target 100-150 workplaces that employ temporary foreign workers, about a quarter of their overall audits.

In one instance, an audit of 20 families who hired live-in caregivers found that only 65 per cent followed the rules. During a sweep of sushi restaurants, which often hire foreign workers or recent immigrants, it found 95 per cent of those audited were not properly paying overtime or for holidays.

"It is a real model for the rest of Canada," said Faraday. "They take the initiative to see if employers are complying [with labour laws]."

Manitoba doesn't always pass on information about companies that broke the rules. For relatively minor problems, their investigators monitor whether employers correct the situation. But for serious offences they alert the federal government.

New Brunswick is in the midst of following Manitoba's lead with the creation of a mandatory registry of employers of temporary foreign workers, scheduled for the fall.

Once that's in place, they say they'll be able to not only track complaints by TFWs but audit their workplaces as well.