The United States has made a big fuss over using NAFTA talks to demand better labour standards in Mexico, but after two rounds of discussions, U.S. negotiators have still not presented any specifics about what they would like to see changed.

A source close to negotiations says this is just one example of how the U.S. team is lagging when it comes to presenting NAFTA proposals, or what negotiators call text.

The source says the U.S. had been expected to present its text on labour standards before the third round of talks, which begin Saturday in Ottawa, but that has not yet happened.

Despite the lack of specifics, the source remains hopeful a deal can be reached by the end of the year.

The optimism is not shared by trade experts or stakeholders, who have suggested it is not possible to overhaul a complex trade agreement in such a short period.

The U.S. and Mexico want NAFTA dealt with before both countries hold elections next year — U.S. voters go to the polls in November for their midterm elections, while the Mexican federal election will be held next summer.

Talks have been scheduled roughly over two-week intervals, and are expected to continue at that pace for months.

Tone change expected

Behind the scenes, talks between Canada, the U.S. and Mexico have been described as professional and broad, since negotiators have mostly been focusing on areas of agreement.

Foreign Affairs Minister Chrystia Freeland will meet with Canada's original NAFTA negotiating team, including former prime minister Brian Mulroney, on Friday. (Associated Press)

But the source says Canadian officials are anticipating a change in tone from U.S. negotiators, given the negative statements made by U.S. President Donald Trump about the deal.

Trump has repeatedly threatened to terminate the agreement if the U.S. does not get what it wants.

The source says Canadian negotiators are expecting their U.S. counterparts to adopt a more aggressive approach to negotiations, to match the mood of the White House.

Digital trade, telecom, small business

A second government official, speaking on background, says talks at this point are where Canadian negotiators had anticipated.

While major breakthroughs have not taken place, the official says progress is being made in several areas including digital trade, telecom rules, and rules for small and medium-sized enterprises.

Detailed discussions on the more contentious issues, including trade dispute mechanisms and rules of origin, have not yet taken place.

The second official expects those conversations to happen later in the renegotiating process, but would not eliminate the possibility both could come up this time.

Ottawa will host the third round of NAFTA talks for five days beginning Saturday. A source close to negotiations remains hopeful a deal can be reached by the end of the year. (Judi Bottoni/Associated Press)

Canada's Foreign Affairs Minister Chrystia Freeland will hold a series of meetings and carefully staged photo ops leading up to the third round of talks.

She will be in Toronto on Friday to sit down with members of Canada's original NAFTA negotiation team, including former prime minister Brian Mulroney.

They will talk trade over lunch alongside Derek Burney, Allan Gotlieb, and Michael Wilson, three former Canadian ambassadors to the U.S.

Earlier in the day, Freeland will meet with members of her NAFTA advisory council. That team includes industry experts, stakeholders and elected officials from across the political spectrum.