TORONTO -- With most countries making a negative COVID-19 test mandatory for passengers travelling by air, some tourists are reportedly obtaining fake test results to get around entry requirements.

Instead of securing a negative PCR test, which may be difficult in time for departure, some travellers are buying counterfeit test results at the airport or from travel agents with instances being reported in Brazil, France and the U.K.

Authorities warn the dangerous practice puts other passengers at risk of contracting the virus despite travel restrictions being in place.

In France, at Paris' Charles de Gaulle Airport, a group of seven people were arrested in September for selling falsified digital certificates intended to prove negative coronavirus test results, .

The group was discovered following an investigation sparked by a traveller leaving France for Ethiopia. The traveller had a fake digital certificate that claimed they tested negative for the virus.

The group was reportedly selling the counterfeit test results for US$180 to $360 apiece.

The seven people have since been charged with fraud and forgery. They face up to five years in prison and a maximum fine of US$445,000 if convicted.

Falsified COVID-19 test results have also popped up in South America.

The Associated Press reported that a were jailed in October for presenting falsified negative test results in an attempt to enter the island of Fernando de Noronha on a private jet.

The island reopened to tourists on Oct. 10 and requires entrants to provide negative COVID-19 test results no older than 24 hours.

Rather than buying fake test results, the group has been accused by local authorities of altering their own results.

In yet another case, a U.K. man that he had doctored the results of a friend's test in order to travel to Pakistan. The newspaper also spoke to another traveller who was offered a fake document by their travel agent.

"You can simply get their negative test and change the name and birth date to your own. You also put a test date on which is within the time limit required," the unnamed man explained in an interview with the newspaper.

"You download the email, change it and then print it."

The man said he doctored the results of his friend鈥檚 test because, during the time he needed to travel, PCR tests were reserved for essential workers or people with symptoms.

"People are doing this as you can't get a COVID test if you have to travel to Pakistan in case of an emergency. It is difficult to get one unless you are a key worker,鈥 he said.

However, as test-result protocols for travel become stricter amid second and third waves across the world, authorities say it is unlikely that many tourists will be able to travel with manipulated documents.

Hawaii, for example, now requires visitors to preregister in their online testing program using an approved testing partner, and upload COVID-19 test results to a digital portal. Paper copies are not accepted.

With files from The Associated Press