WINNIPEG – Canadian Prime Minister Justin Trudeau on Tuesday urged legislators to quickly approve a new continental trade pact but the main opposition party said it wanted to study the deal, indicating the ratification process could drag on.

Canada is the only one of the three signatories not to have formally blessed the United States-Mexico-Canada Agreement (USMCA) deal and officials fret the process may well last until April. This could irritate US President Donald Trump, for whom the pact was a major political victory in an US election year.

Trudeau said his minority Liberal government would unveil legislation on January 29 to ratify the USMCA, which will update the 25-year-old North American Free Trade Agreement (NAFTA).

"We are going to make sure we move forward in the right way and that means ratifying this new NAFTA as quickly as possible," Trudeau said while flanked by members of his cabinet following a three-day retreat in Winnipeg, Manitoba.

Free trade is critical to the economies of Canada and Mexico, which both send around 75% of goods to their much larger neighbor.

The Liberals though no longer control the House of Commons and passing legislation requires the cooperation of other parties, which can if they wish slow down the process.

The main opposition Conservative Party, which complained the Liberals had not answered earlier questions about the USMCA, said it wanted to examine what it called potentially worrying aspects of the deal.

"We definitely want to give it the proper due diligence to shine a light on some of the unique (aspects)," said Randy Hoback, the party's spokesman on trade, expressing concern about possible damage to the dairy and aluminum sectors.

"I don't think anybody has any intention of dragging anything out. We just want to make sure we do our job ... there are some things in this deal that I think the business community isn't aware of that we need to shine a light on," he said in a phone interview.

The USMCA, which includes tougher rules on labor and automotive content, cannot take effect until it has been ratified by all three member nations.

Last week, the United States Senate overwhelmingly approved the legislation sending the measure to Trump for him to sign into law.

Trump made the renegotiation of NAFTA a key element of his 2016 presidential election campaign, calling it the "worst trade deal ever made."