A missing person is feared dead, and at least 22 were injured, after a roof-top car park collapsed into a mall in Canada.

The collapse happened on Saturday afternoon, when the mall is typically crowded with shoppers.

At least one parked vehicle as well as concrete and metal fell into the two-story mall below, leaving a hole in the roof.

Opening up a large, rectangular space and a clear view of the retail space below, photos taken soon after the collapse showed several vehicles remained parked on the undamaged part of the roof-top.

Extraction teams, including dogs trained to locate people trapped underneath debris, were standing by as crews worked to stabilize the site, which was still too dangerous to enter.

Authorities said they have compiled a list of people who have been reported missing in the area but could not confirm how many were on the list.