After a month-long pause, the federal government is bringing back random, mandatory COVID-19 tests for vaccinated travellers arriving at Canada's four main airports.

Ottawa paused the tests in mid-June as it faced criticism from tourism and air travel groups about the chaos at Canadian airports.

The government also said it planned to move the tests themselves to locations outside of airports.

That means that when the tests resume next week, they will completed either at an in-person or virtual appointment.

The rules apply to fully vaccinated travellers arriving at airports in Toronto, Montreal, Vancouver and Calgary.

Those who aren't fully vaccinated must test on both the first and eighth days of their mandatory 14-day quarantine, unless they are exempt.

The Conservatives say the Liberal government has not adequately explained the scientific justification for its pandemic restrictions, especially the random testing of fully vaccinated travellers.