The affected checkpoints are at Carievale, Estevan Highway, Northgate and Oungre. Click here for details.
Last week, the agency had reduced hours of service at 27 low-traffic ports of entry.
The Covid-19 related measures are temporary, and will remain in effect until further notice, the CBSA said.
Canada and the U.S. introduced border restrictions in late March to limit the spread of the virus. The restrictions were extended for another month last week.
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