A Red Deer mom has told of her anguish after watching her son being detained at the Calgary airport, loaded into a van, and taken to an undisclosed isolation centre.

Rebekah McDonald was at the airport late Saturday night, hoping to welcome her son, Ethan, back to Calgary from Arizona.

McDonald hadn't seen her son for two years.

But the joy soon turned to tears when her son was taken into custody for having what the Canadian federal government considers the wrong COVID-19 test.

"They are saying it's not accurate and they are wanting to take him to a quarantine facility. They won't let me talk to him. They won't let me see him. They won't come and talk to me. The border patrol services say they have nothing to do with it – they won't tell me who has to do with it," said McDonald in a social media video as she walked through the airport concourse.

"They won't tell me who's picking him up. They won't tell me where he's going. They won't tell me anything.

"They say he doesn't have a choice, that it's the law. They say I don't have the right to talk to him. They are taking him against my will and his will and I'm not okay with it. I don't know what to do about it and I don't know where I'm supposed to find him.

"I'm freaking out," said McDonald, dissolving into tears.

In a bid to level off the number of COVID-19 cases being brought in by returning travellers, Prime Minister Justin Trudeau announced Friday upon their arrival back in Canada, they will be taken to an isolation facility and given another coronavirus test.