Blunt warnings about the fate of the North America Free Trade Agreement suggest Canada needs to prepare for a world without the trade pact.

"This thing is going into the toilet," said Jerry Dias, the head of UNIFOR, Canada's largest private sector union.

Dias said it is clear the Americans are not looking to reach an agreement, and he scoffed at the idea of negotiations being completed before the end of the year.

"We are going to have to start having serious conversations about life after NAFTA," Dias said.

The stark assessment comes in the middle of the fourth round of NAFTA talks — negotiators from Canada, the U.S. and Mexico are meeting behind closed doors at a hotel in suburban Virginia, just outside of Washington.

Prime Minister Justin Trudeau acknowledged yesterday that the NAFTA renegotiation process has been difficult, following his meeting with U.S. President Donald Trump at the White House.

Trudeau was looking for reassurance from Trump over the importance of trade with Canada, but instead Trump mused about killing the three-country pact in favour of a bilateral trade agreement with Canada.

Trudeau takes part in a roundtable discussion with civil society leaders in Mexico City. (Sean Kilpatrick/Canadian Press)

Speaking in Mexico, where he held a joint media event with Mexican President Enrique Pena Nieto late Thursday, Trudeau said improving NAFTA was the best way to improve the lives of North Americans.

Pena Nieto said what was important was happening at the negotiating table and everything else was "speculation."

Trudeau also said that despite the unpredictability of the negotiating process and surprising decisions made by the U.S. administration, Canada would remain at the table.

"We will continue to take seriously the work we do and we will not be walking away from the table based on proposals put forward," Trudeau said. "We will discuss those proposals, we will counter those proposals, and we will take seriously these negotiations."

Growing pessimism

Trump's threats are being taken seriously by members of the government's NAFTA advisory panel, including former Conservative cabinet minister James Moore.

"I think it's a real threat and the odds are even, frankly, that it may happen," Moore told CBC News Network's Power & Politics.

"If you look at President Trump, if you look at the sweep of what he's done so far as president, he's had very little success at proactively gaining things, but he's had an actual success at taking things down," Moore said.

Trump's threats to kill the deal are more than just discouraging, said NDP trade critic Tracey Ramsey.

"It confirmed the fact that the U.S. aren't in negotiations in good faith," Ramsey said during a phone interview with CBC News.

She also suggested that Canada may be wasting its time and resources trying to renegotiate a deal when the U.S. isn't convinced it can be saved.

"I'm concerned that this is all for some type of show. When we hear the president, sitting next to the prime minister, say that he isn't confident that we can get a deal, it reinforces that," she said.

Canada will survive: Dias

Conservative foreign affairs critic Erin O'Toole said that saving NAFTA is in the U.S.'s national interest — with nine million jobs in that country depending on the trade pact — but he remains concerned.

"I'm more worried now than I was before the visit by the prime minister," said O'Toole.

"While it seems [Trudeau] has a good personal relationship with the president, each week … NAFTA appears more at risk than ever," O'Toole said.

Despite the negative statements and lack of progress, Dias said Canada will survive if the trade deal does not.

"We have a heck of a lot to offer the global scale … we are a nation that's rich in natural resources and raw materials," Dias said. "Canada's not shooting from a position of weakness here at all."

While there are big legal questions about what could happen if the U.S. terminates NAFTA, Canadian officials suggest trading rules would fall back to the original Canada-U.S. free trade agreement, negotiated in the late 1980s.

If that happens, Canadian officials suggest that free trade agreement would also have to be modernized, meaning new trading talks would be needed.