Canadian border agents and airlines are being warned to be on the lookout for tampered Canadian visas from Chinese nationals coming from Shanghai and the Ethiopian capital of Addis Ababa, but Ottawa is being tight-lipped about the extent of the problem and threat to this country's security.

Public Safety Minister Ralph Goodale confirmed to The Globe and Mail that there has been a significant spike in Chinese nationals who have been caught carrying altered Canadian visa documents to gain illegal entry into Canada. He was unable to explain how genuine Canadian temporary resident visas ended up in the hands of forgers.

"Whoever the traveller may be, it is important that border officers be alert to the risks and the dangers," Mr. Goodale said in an interview. "I can't comment on any specific situation but I can say that our officials are alert to the risk and they are very, very assiduous at detecting illegitimacy and making sure that our system maintains its integrity."

Story continues below advertisement

David Mulroney: Trudeau's embrace of China exposes his naïveté

The Canada Border Services Agency declined to say whether these fraudulent visas are being used by spies, criminals, economic migrants or bogus refugees. The Globe and Mail obtained the confidential alert that was issued last Thursday.

"An alert is an internal CBSA mechanism providing information on issues of concern for CBSA staff in Canada and abroad," the agency said in a brief statement. "Where relevant, the CBSA shares information with its partners to identify border-related threats to protect the safety and security of Canadians."

Temporary resident visas (TRV) are issued to tourists, foreign workers and international students, usually for a period of six months. Criminal, security and medical background checks are conducted before a visa is issued.

Like other countries, Canada outsources the processing of visa applications in China. Private companies submit them on behalf of Chinese applicants.

A senior Canadian border-security source, who spoke on background, said China's intelligence agencies are too sophisticated to use forged temporary visas to send spies into Canada. But almost anyone else wanting to get into Canada would be happy to pay for such a document, the source said.

"You have people coming in here who want to be under the radar. It could be criminals who want to come in here under an assumed identity. It could be business people who are inadmissible or they have been told they can't come back to Canada, or people who have been refused a visa so now they are trying to get a bogus visa or refugees," the source said.

Story continues below advertisement

The CBSA sent out the alert on Feb. 2, saying "there has been a significant increase in the use of altered" temporary visas originating from Shanghai and Addis Ababa. Some of the people carrying these documents have "been intercepted abroad and/or arrived undocumented in Canada," according to the alert.

"The security features of the TRV are genuine, however, the original personalization has been replaced with fraudulent information," the agency said.

It urged border agents "whenever possible" to obtain passenger information prior to a commercial flight's departure to Canada. Agents were also instructed on how to identify signs of document tampering.

There are as many as 60,000 Chinese nationals living and working in Ethiopia, a hot spot for investment from China over the past decade.

China is among the top origin countries for immigration fraud aimed at smuggling people into Canada. Shanghai is known as a city where forgery rings sell visas to foreigners looking for work in China and for Chinese nationals seeking to leave their country.

Many of the individuals trying to defraud Canada's visa program are from the same socioeconomic groups or regions that once paid smugglers – also called "snakeheads" – as much as $70,000 to arrive illegally on Canada's shores by boat, government briefing documents show.

Story continues below advertisement

Vancouver immigration lawyer Richard Kurland said a false visa may also help Chinese people seeking to travel to other countries because possessing one suggests Canada has already rated the bearer a low-risk individual.

He said it's likely economic migrants are the most frequent users of these fake visas.

One former Canadian government official, who spoke on condition of anonymity, said some fake visa holders may very well be Chinese nationals wanted by Beijing for alleged criminal activity.

The Trudeau government has ambitious plans to boost the number of Chinese visitors to Canada, and last fall, the Prime Minister announced that Ottawa will open seven additional visa-application centres in China.

Canada is an extremely popular destination for Chinese citizens seeking temporary residence in North America.

The numbers of Chinese obtaining 10-year temporary resident visas – which allow them to stay in Canada for up to six months, each year, for a decade – has exploded in popularity.

Story continues below advertisement

In 2012, 82,636 of these Canadian visas were issued to Chinese citizens and in 2015, 337,393 were issued.

Since these visas are good for 10 years, it means more than a million Chinese citizens currently hold these documents, which allow them temporary residence in Canada.