The new North American trade deal is expected to take centre stage when Parliament returns Monday, marking the first challenge for a Liberal minority government that will need Opposition support to pass legislation.

The House of Commons reconvenes Monday after rising for the holidays in December, giving Canadians their first serious look at Canada's 43rd Parliament in action.

Moving forward with the Canada-United States-Mexico Agreement (CUSMA) will likely dominate the agenda this week when the Liberals table a bill to approve the deal Wednesday.

On Sunday, Deputy Prime Minister Chrystia Freeland penned a letter to Opposition parties urging leaders to work together to pass the legislation behind the new agreement.

"I write to ask for your views and your support, as we, and our colleagues in the House of Commons, begin the vital task of debating the Canada-U.S.-Mexico-Agreement," Freeland said.

"No one, least of all the prime minister or me, expects anything other than a full, frank, and vigorous debate about the new NAFTA," she wrote. "That's exactly as it should be."

Today I wrote to Opposition Leaders <a href="https://twitter.com/AndrewScheer?ref_src=twsrc%5Etfw">@AndrewScheer</a>, <a href="https://twitter.com/yfblanchet?ref_src=twsrc%5Etfw">@yfblanchet</a>, <a href="https://twitter.com/theJagmeetSingh?ref_src=twsrc%5Etfw">@theJagmeetSingh</a>, and <a href="https://twitter.com/JoAnnRobertsHFX?ref_src=twsrc%5Etfw">@JoAnnRobertsHFX</a>, asking that we work together, as colleagues, to put Canada and Canadians first and ratify the new <a href="https://twitter.com/hashtag/NAFTA?src=hash&ref_src=twsrc%5Etfw">#NAFTA</a> swiftly. <a href="https://twitter.com/hashtag/CdnPoli?src=hash&ref_src=twsrc%5Etfw">#CdnPoli</a> <a href="https://t.co/2NqvHecw3U">https://t.co/2NqvHecw3U</a> —@cafreeland

"I ask that we work together, as colleagues, to put Canada and Canadians first, and get this important work done without undue delay," Freeland added, echoing a similar call issued by Canada's premiers last week.

Both NDP Leader Jagmeet Singh and Bloc Québécois Leader Yves-François Blanchet are pushing for a full debate of the agreement in the Commons as well as studying the issue at committee.

The Conservatives are also calling for further study, but don't seem eager to delay the deal.

In response to Freeland's plea, Green Party interim leader Jo-Ann Roberts said the party was feeling "fairly positive" about supporting the new agreement.

Pharmacare NDP's priority

Meanwhile, the NDP said that creating a national pharmacare program will be its first piece of private members' legislation, though it doesn't expect to table a bill until next month.

The party also says it will be pushing for the Liberals to comply with a 2016 Canadian Human Rights Tribunal ruling to end Ottawa's discrimination against First Nation children harmed by the on-reserve child welfare system and under-funded child and family services.

NDP Indigenous youth critic Charlie Angus put forward the motion in December after Prime Minister Justin Trudeau sought judicial review of the tribunal's decision in October. (Sean Kilpatrick/The Canadian Press)

The House of Commons unanimously passed an NDP motion in December that could compel the federal government to abandon its Federal Court appeal regarding a decision ordering Ottawa to compensate the children and their families.

The party will also be keeping an eye this week on a ways and means motion on the Liberals' proposed tax changes that will raise the threshold of income exempt from federal income tax.

Other issues in play

The Green Party will focus on preventing Ottawa from approving Teck Resources' bid to build a proposed oilsands mine in Alberta, calling for federal officials to meet nation-to-nation with Wet'suwet'en members protesting the Coastal GasLink pipeline on their traditional territory and asking ministers responsible for Canada's new medical assistance in dying criteria to address a number of the party's concerns.

Justice Minister David Lametti plans to table new legislation for the criteria in February.

On Saturday, Conservative Leader Andrew Scheer said he would be following the Liberals' handling of Canada-China relations.

"The China committee is up and running and we're going to be holding the government's feet to the fire on their relationship with China," Scheer said, ahead of the committee's second meeting Monday.

Leader of the Opposition Andrew Scheer said that despite an ongoing race for Conservative leadership, the party would still focus on highlighting problems within the Trudeau government. (Adrian Wyld / Canadian Press)

Scheer commented last week that the Conservative leadership race would not distract the party from holding the Liberals to account when Parliament resumes.

"The Trudeau Liberals might think that our leadership race will give them a free ride. They're wrong," he said. "We're all going to continue to be here in Ottawa and the House of Commons and on the committee floor every single day fighting for our vision for the country."

The Conservatives also said in an email that the party plans to bring forward an opposition motion Tuesday, but wouldn't provide further details.