TORONTO -- A single farm in Windsor-Essex, Ont. has been linked to 175 new cases of COVID-19 in the province, reigniting concerns about the rapid spread of the virus among temporary foreign workers.

Ontario reported 257 new cases of COVID-19 on Monday, 177 of which were confirmed by the Windsor-Essex public health unit following targeted testing of migrant farm workers over the weekend.

Officials noted that one farm, which employs approximately 450 workers, is the source of 175 of those cases.

“These recent outbreaks are concerning and they pose unique challenges that require a targeted response,” Dr. Barbara Yaffe, Ontario’s Associate Medical Officer of Health, said during a press conference Monday.

More than 1,000 agricultural workers have been diagnosed with COVID-19 in Ontario since the start of the pandemic, according to the advocacy group Justice for Migrant Workers.

Two temporary foreign workers from Mexico have died from the disease in the Windsor-Essex region. A third migrant worker who was employed on a farm near Simcoe, Ont., also died after testing positive.

Growing case numbers among farm workers have ignited calls for Ontario to shut down the agricultural sector entirely until adequate sanitation and safety measures can be implemented.

“The industry must immediately cease production and, as a society, we must demand that the interests of the workers are paramount, not the profits of a billion-dollar industry,” Justice for Migrant Workers spokesperson Chris Ramsaroop said in a statement to CTVNews.ca.

“Our message to provincial and federal politicians -- stop murdering migrants by your inactions.”

Those who live and work on the farms say they are subjected to living conditions that make it nearly impossible to contain the spread of the virus.

"We have rooms that are three metres by three metres. Four people sleeping in beds that are in very poor condition. Mattresses that are used and spent, and bedding that is in bad conditions," an employee identified only as Francisco to protect his identity told CTV News.

Syed Hussan, executive director of the Migrant Workers Alliance for Change, says many workers aren't paid if they are off sick from work, preventing them from sending home money to loved ones that rely on it. Some allege WiFi access has even been cut off.

"Because we don't have proper rights, they step on our necks," Hussan told CTV News in Toronto.​

Both the Ontario and federal government have pledged to ramp up inspections and oversight at farms to fight the spread of COVID-19.

"We have a great team out there and we're going to do everything in our power to resolve these cases as soon as possible," Ford said Monday, noting that the province is taking action against “fly by night” recruitment agencies that may be skirting rules put in place to protect workers during the pandemic.

Last week, the province released a three-point plan to reduce the risk of transmission of COVID-19 on farms, including expanded on-site testing at agri-food businesses and access to emergency benefits and supports for foreign workers.

But it also allows farm workers infected with the virus to continue work as long as they are asymptomatic.

When asked if the spike in new cases would alter those plans, officials did not comment directly, instead noting that public health inspectors are working to determine whether or not those who have tested positive are asymptomatic.

“Windsor-Essex has sent a team of public health nurses and inspectors out to the farm that has the majority of the cases to re-interview them, determine whether they have symptoms, and determine the best next steps in terms of controlling the outbreak,” said Yaffe.

“At the end of the day the employer is responsible for ensuring that other workers are not at risk.”

Officials noted that shutting down the farm is a “consideration” as the investigation continues.

Justice for Migrant Workers is calling on the government to change its plan to ensure that all workers who test positive are quarantined, even if they are asymptomatic. The organization also wants to see workers put into hotels and provided individual rooms to prevent the further spread of the disease.

Mexico's Ambassador to Canada Juan José Gómez Camacho has warned that any farm that fails to follow COVID-19 precautions will not receive help from Mexican workers.

"Let me say something. Any farm that does not follow the rules will certainly not receive any Mexican work," Gómez Camacho told CTV’s Power Play last week.

Mexico halted their temporary foreign worker program earlier this month due to concerns over the spread of the virus amongst farm workers, but later reinstated it after Canada pledged to ramp up inspections.

- With files from CTV News' Heather Wright

Correction:

An earlier version of this story misidentified Mr. Syed Hussan. He is the executive director of the Migrant Workers Alliance for Change.