TORONTO -- A group of employees who work the same shift at a Canada Post facility in Mississauga have been sent home and advised to isolate to prevent further spread of COVID-19 as the number of cases at the site continues to climb.

The Crown corporation said 350 employees and contractors who worked on the afternoon shift (shift 3) in Gateway East were instructed to leave the Dixie Road location Friday evening and told to self-isolate for 14 days.

"This precautionary measure was recommended by Peel Public Health late Friday, January 22 as the most effective way to control further spread at this stage," Canada Post said in a statement.

Shift 3 workers who were not working Friday are also being told not to return to the facility for two weeks from the last day they were in the facility.

Public health officials conducted rapid testing of shift 3 workers earlier this week, which resulted in 42 positive tests. So far, a total of 190 workers have tested positive for COVID-19.

"Given the significance of the Gateway facility within our processing network, we are evaluating and adapting our existing contingency plans to manage the impact on customers," said the Crown corporation.

When asked if mail or parcel delivery could be affected, a spokesperson for Canada Post said customers should track their packages online or on its app.

Canada Post noted that rapid on-site testing will also begin next week for employees working on shift 2. Those who refused to be tested will need to self-isolate for 14 days.

Enforcement of safety protocols will continue at the facility, Canada Post said, with an increased focus on washrooms, lunchrooms and locker rooms.

Meanwhile, the Canada Border Services Agency said its officers working at the facility had been moved to the main floor to the upstairs mezzanine area to limit contact with Canada Post employees.

"International mail continues to be processed by CBSA officers at the CPC satellite facility located at Toronto Pearson International airport," a spokesperson for the agency said in a statement.

There are no known COVID-19 cases among officers linked to the outbreak, and there have been no positive cases among CBSA staff at the facility since November 2020, the agency said.

More than 4,500 employees work in mail processing, technical services, transportation, casual and administration at the facility.