Prime Minister Justin Trudeau is knocking Conservative Leader Pierre Poilievre's call for the federal government to close the Roxham Road irregular border crossing in Quebec as a "simplistic solution," saying the best approach is to renegotiate the Canada-U.S. migrant pact known as the Safe Third Country Agreement.

"Could somebody put up barricades and a big wall? Yes. If Pierre Poilievre wants to build a wall at Roxham Road, someone could do that. The problem is we have 6,000 kilometres worth of undefended shared border with the United States, and… people will choose to cross elsewhere," Trudeau said Wednesday.

"The only way to effectively shut down not just Roxham Road, but the entire border, to these irregular crossings is to renegotiate the Safe Third Country Agreement, which is serious work that we are doing as a government right now."

On Tuesday, Poilievre called for the federal government to present a plan to close the crossing at Roxham Road along the Quebec-New York border within a month, suggesting it can be done as it was for some time during the COVID-19 pandemic. In a press conference on the topic, the Conservative leader accused Trudeau of encouraging irregular crossings there, after failing to find a solution for years. 

"If we are a real country, we have borders. And if this is a real prime minister, he is responsible for those borders," Poilievre said. "He's had six years since the influx began. It is his job to close the border and we're calling him to do it."

The prime minister said Wednesday that while "simplistic solutions" won't be how it's done, the government has for years -- alongside the U.S. -- been looking at ways to completely but compassionately close off all irregular crossings.

"We're making real progress," said the prime minister. 

This comes on the heels of Quebec Premier Francois Legault putting the issue back on the national political agenda by asking Trudeau to make renegotiating the Safe Third Country agreement a priority when U.S. President Joe Biden visits next month. Legault says that agreement has resulted in an increased and disproportionate flow of migrants into Quebec, which Trudeau has acknowledged.

"We will continue to be there for Quebec, we will continue to be there for our international obligations, and we will continue to be there to try and make sure that we have a safe and secure and rigorous immigration system," he said. 

Federal figures show more than 39,000 people claimed asylum after crossing into Quebec by land in 2022. 

The cross-border agreement was first signed in 2002 and, despite some recent tweaks, talks about modernizing it have been ongoing since 2018. Under the pact, people seeking refugee status in either Canada or the U.S. must make their claim in the first country they enter.

The loophole that the agreement applies only to official land border crossings means asylum seekers who manage to enter a country via an unofficial crossing — such as Roxham Road— are not returned.

In March 2020, the government began turning away asylum seekers as part of a series of border measures aimed at limiting the spread of COVID-19. The policy was kept in place until late 2021, and resulted in more than 500 migrants being turned away, according to Reuters. Trudeau said Wednesday this approach was "reasonably effective." 

'RECKLESS' APPROACH TO VALID CONCERNS: MINISTER

Canada's Minister of Immigration, Refugees and Citizenship also weighed in Wednesday on Poilievre's suggestion, calling it "reckless" while noting that the concerns Legault is raising are valid.

"It's reckless and frankly, not a thoughtful approach to simply say 'within 30 days, you close Roxham Road,'" Fraser told reporters during a media availability in Dartmouth, N.S. on Wednesday morning.

"If we took such an approach rather than actually dealing with people with dignity and respect… The result would likely be serious risks that would fall upon vulnerable migrants who are seeking safe haven in Canada, who would be forced to potentially cross through a dangerous portion of the border not knowing how the elements — particularly at this time of year — would impact themselves and their family."

Fraser said Wednesday that Legault is right to raise the issue, noting that Quebec is facing disproportionate pressure on the province's social services as well as its health and education systems. He nevertheless called Poilievre’s approach: "brash bumper sticker arguments that seek to gain political favour in a time of a real challenge."

"It's a time to solve problems through adult conversations with our most important strategic trading partner in the United States," Fraser said, pointing to ongoing conversations between Canadian officials and their American counterparts towards a "lasting solution."

WORK UNDERWAY TO SPEED UP CLAIMS, MOVE MIGRANTS

Work is also underway across the country, Fraser noted, to fund communities in other provinces, including in Ontario and Atlantic Canada, which would have the capacity to accommodate additional asylum seekers.

"Because it's not fair or right that one community or one province ought to bear the brunt of a challenge that we're facing as a result of Canada abiding by its domestic and legal obligations," Fraser said.

Poilievre is also pushing the federal government to speed up the processing of refugee claims, saying that while Canada needs more immigrants, "we need to have it done in an orderly and lawful fashion." 

Responding to a question about immigration processing times, Fraser said that improvements are being made towards tackling what became a massive backlog, allowing his department to process more claims on time, seeing 5.1 million applications assessed last year.

"The fact that Canada has become the most popular country in the world for workers to move to, we're facing demands like the immigration system has never seen," Fraser said. 

With files from CTV News' Spencer Van Dyk