Canadian negotiators are still meeting behind closed doors with USA counterparts.
The U.S. had given Canada until Sunday to join the new deal or watch as the U.S. and Mexico went ahead without it.
Several Democrats questioned whether the Trump administration has the legal authority to proceed with a Mexico-only deal when prior notifications under the "fast-track" trade negotiating authority law were for a trilateral deal including both Mexico and Canada.
Meredith Lilly, an global trade expert at Carleton University in Ottawa, said there's virtually nothing in the text that will take Canadian negotiators by surprise.
Monday is an important date in the NAFTA calendar: Congress has declared an October 1 deadline for Canada to join an existing agreement between the USA and Mexico in time for a vote on Capitol Hill, and it's also the day voters in Quebec go to the polls.
"We're very unhappy with the negotiations and the negotiating style of Canada".
The Canadian dollar dropped on Friday and finished at the best levels of the day on reports Mexico was insisting on a trilateral deal.
Earlier, the president-elect of the mexican Andres Manuel Lopez Obrador had assured him that there was no deadline in the trade negotiations between Canada and the United States on the modernisation of the agreement.
"We will keep working as long as it takes to get to the right deal for Canada", Trudeau told reporters at the United Nations.
'He said the negotiations were very hard, that it might not be possible (to reach a three-way deal), but that they (Canada) had made a proposal, ' he said. Canada is represented by a team of NAFTA negotiators led by Foreign Affairs Minister Chrystia Freeland. The Dairy Farmers of Canada lobby group did not respond to a request for comment.
"The U.S. knows what they need to do to get a deal, so it's really up to them", said one, speaking on condition of anonymity given the sensitive nature of the talks.
The US and Canada remained deadlocked over various trade provisions.
Mexican ambassador Dionisio Perez Jacome said his country still wants Canada to come on board, regardless of congressional deadlines. The administration had set a weekend deadline for Canada to join, a schedule created to allow Mexican President Enrique Peña Nieto to sign the deal before leaving office and being succeeded by incoming President Andres Manuel Loprez Obrador.
Canadian President Justin Trudeau this week fired back, saying, "Americans are finding that the negotiations are tough because Canadians are tough negotiators, as we should be", Reuters reported. The United States has said that Mexico agreed to eliminate a system of settlement panels to arbitrate disputes over anti-dumping and anti-dumping tariffs.
Talks remain snagged on several issues, including US demands for greater access to Canada's dairy market and Canadian resistance to scrapping a dispute settlement procedure. "This president has always been a bit of a showboat and I think Canadians have become accustomed to this".
The text is expected to conform to details previously released on tighter automotive rules requiring an increase in regional value content to 75 percent from 62.5 percent previously, with 40-45 percent coming from "high wage" areas, effectively the United States. "In any case, we already agreed with the USA and we won't revise what is agreed".
The U.S. and Canada have been hung up on some core issues.