MONTREAL, Jan. 21 (Xinhua) -- Canada is preparing for the worst in case U.S. President Donald Trump decides to pull his country out of the North American Free Trade Agreement (NAFTA), said a Canadian NAFTA advisor on Sunday.

"The consensus felt like it's not if, it's when he's going to pull the plug," said Rona Ambrose, member of Canada's NAFTA advisory council and former interim leader of the Conservative Party and the leader of the opposition between 2015 and 2017.

Ambrose's remarks came as the sixth round of talks between Canada, Mexico and the United States began in Montreal on Monday. The talks are set to wrap up on Jan. 29.

"I really believe Canada is doing everything that we can," Ambrose added. "I think we just need to ramp up all those measures even more in the next week or so."

Canadian Foreign Affairs Minister Chrystia Freeland, who is Canada's lead negotiator on NAFTA, said that Canada is "absolutely" preparing for a Plan B.

"It is no secret -- in fact, it is absolutely a matter of public record, that the U.S., including the president, has said quite clearly that they have thought about invoking Article 2205, which would set the clock ticking on the six-month withdrawal notice," she noted.@ "I think that it is only sensible and prudent for us to take the president at his word. So we are absolutely prepared for every eventuality," she said.

However, Freeland remains hopeful that NAFTA will survive.

"We also approach these negotiations ... with a spirit of goodwill and positive intent. And we're going to be working hard to get a positive result," she said.

Freeland denied reports that Canada's insistence on the so-called "progressive" chapters in NAFTA, covering labour standards, gender equality, indigenous rights and the environment, has been a sticking point for the United States.

"I'm really proud that, in Montreal, for the first time ... we're going to have a table devoted to discussing the indigenous chapter,' Freeland said.

"Having said that, these progressive elements have in no way been the sticking point in these negotiations," she said.

Freeland said the key sticking points are unconventional U.S. proposals, like Chapter 19, and rules of origin.

Chapter 19 is the agreement's dispute resolution mechanism. Rules of origin refer to provisions on how much foreign content, such as autoparts, can be included in a product without tariffs.

Ambrose said she does not believe the progressive chapters are actually a sticking point, but rather something the Americans will use to paint Canada as uncooperative. "They're positioning themselves, so they'll be able to pull out," Ambrose said.