OTTAWA -- Police have been notified for follow-up in more than 21,000 cases where travellers arriving in Canada either couldn't be reached or showed "indication of non-compliance" with the mandatory 14-day quarantine rules.

Of the 21,422 referrals from the Public Health Agency of Canada (PHAC) to the RCMP, nearly 1,500 were identified as "priority cases" for physical check-ups.

The RCMP and PHAC both confirmed the figures to CTV News -- though few punishments have been doled out to any suspected rule-breakers.

"To date, 9 tickets have been reported to PHAC as being issued under the Contraventions Act for offences under the Quarantine Act, four of which were issued following a request made by PHAC for a physical verification (2 fines were issued by RCMP and 2 by the Ontario Provincial Police)," PHAC spokesperson Geoffroy Legault-Thivierge confirmed in an emailed statement sent to Tuesday evening. "As of July 9, 2020, no arrests have stemmed from PHAC-requested physical verification checks."

In addition to these latest figures, Canada Border Services Agency (CBSA) confirmed to that some travellers indicated a desire not to comply with Canada’s rules as early as the moment they travelled across the border.

"As of July 3, 2020, the CBSA has referred information to both PHAC and the RCMP on 237 travellers who the CBSA believes may not have respected the requirement to quarantine or isolate and/or those who have signalled an unwillingness to comply," said CBSA spokesperson Rebecca Purdy in another emailed statement on Tuesday.

Canada shut its borders to foreigners in mid-March, initially exempting U.S. residents from the new rules. But within days the Canada-U.S. border had also shuttered to all non-essential travel, an agreement that sources told CTV News on Tuesday would be extended to August 21.

As Canada shut its borders to all non-essential foreign travel, it also imposed a mandatory 14-day quarantine rule on March 21 for any travellers who do squeeze past the tightened ports of entry.

According to Deputy Chief Public Health Officer Dr. Howard Njoo, most travellers are happy to play by the rules.

"Most people from what I've seen, in terms of the data that’s come in, have been very good in terms of what we call compliance. They accept the calls, they recognize that we’re doing it not to badger or hound them, but really as a gentle reminder to continue doing what's, I think, in their best interests in terms of their health, but also to protect others," Njoo said in a Tuesday press conference.

The news of thousands of suspected rule-breakers emerges as COVID-19 cases explode on the other side of the world's longest international border.

At the end of June, the U.S. became home to the world's highest number of reported infections: more than 2.2 million. That number has since soared to more than 3.4 million, according to the New York Times, with more than 136,000 deaths.

Njoo had a message for anyone who is travelling to Canada and is considering flouting quarantine rules.

"If you are coming from outside of Canada, please understand all of the efforts that Canadians have done inside of Canada to flatten the curve and to make sure that the transmission of the virus is as low as possible," Njoo said.

"Please do your part."

With files from CTV National News' Annie Bergeron-Oliver