Mexican migrants
The White House revealed that there has been more than 300,000 encounters with unaccompanied minors at the US-Mexico border this year. STRINGER/AFP

The Canadian government has launched a crackdown on Mexican nationals visiting Canada.

Senior federal government sources told Radio-Canada that a series of visa requirements on Mexican nationals will be reinforced.

The new rules, which will see all Mexican nationals requiring a visa to enter Canada, were put in place on Thursday this week.

The limitations on travel come after Quebec Premier François Legault urged the federal government to increase visa restrictions to decrease the influx of asylum seekers into the province.

During a meeting with Canada Prime Minister Justin Trudeau, Legault said that many Mexican asylum seekers have been entering Quebec through Canada.

In a letter to Trudeau, the Quebec Premier said: "The possibility of entering Canada from Mexico without a visa certainly explains part of the influx of asylum seekers."

"Asylum seekers have trouble finding a place to live, which contributes to accentuating the housing crisis," Legault added. "Many end up in homeless shelters, which are overflowing."

According to the Coalition Avenir Québec (CAQ) government, the costs of welcoming migrants to the nation has surpassed $1 billion.

Official data, published by the Immigration and Refugee Board of Canada, show that more than 25,000 Mexican nationals have applied for asylum in the country last year.

The statistics also showed that the backlogged asylum claims from Mexico, which have been filed with the Immigration and Refugee Board, currently measures at more than 28,000.

The U.S. government has also been calling on Ottawa to reinforce the visa requirements for Mexican travellers, in an attempt to also curb the increased number of migrants crossing into the US from Canada.

This comes after the US Customs and Border Protection Agency revealed that the White House has seen its most encounters with unaccompanied minors at the US-Mexico border this year - measuring more than 300,000.

For years, Mexican nationals were permitted to travel to Canada without a visa.

However, while migrants must be visa holders to enter the US, border officials have reported cases of Mexican nationals using Canada's visa-free rule to cross into Canada and to relocate illegally in the US.

It has been estimated, by Canadian government sources, that the new visa regulations will impact around 40 per cent of all Mexican nationals travelling to Canada.

In 2009, led by Prime Minister Stephen Harper, Canada's right-wing government implemented a visa requirement on Mexico.

The visa was put in place to stem the flow of Mexican asylum claims but when Trudeau came into office in 2016, the government relaxed the restrictions.

Ahead of the visa requirement announcement, Mexican President Andrés Manuel López Obrador pointed his finger at Canada for attempting to act unilaterally on immigration measures.

At a press conference, López Obrador argued: "They are in negotiations to reach an agreement so that we can control migratory flows from Canada."

"We have acted generously with them, with the government of Prime Minister Trudeau, but they were already on the verge of applying unilateral measures," he added.

López Obrador went on to warn world leaders that he will reconsider his invitation to the next North American Leaders summit, set to be held in Canada, if Canada and the US continue to treat his country unfairly.

"If there's no respectful treatment, I won't go," he declared.

The new rules won't amount to a complete return to the pre-2016 rules and those who have already received valid visas under the previous system within the last ten years are exempt from reapplying under the new requirements, a government source said.

Mexican nationals who are relocating to Canada on study or work permits, will also be exempt from reapplying under the new requirements.

Once they have obtained a new visa, which will remain in place for a ten-year period, Mexican travellers are permitted to enter Canada multiple times and to stay for up to six months at a time.

Another government source said that the new visa restrictions will also give customs officers the discretionary power to limit the duration of the visa or the number of visits.