MONTREAL -- Canada's European trade envoy says he's hopeful a landmark trade agreement with the European Union will be approved later this week, despite snags that have stalled a critical vote on the deal.

Pierre Pettigrew expressed his optimism after speaking to the Montreal Board of Trade on Tuesday while overseas, EU officials took pains to save a pact that has been years in the making.

The fate of the so-called Comprehensive Economic and Trade Agreement (CETA) remains unclear because of opposition from Wallonia. The francophone southern region in Belgium has expressed concerns the deal could erode labour, environmental and consumer regulations.

Thanks to Belgium's complex political system, Wallonia has the power to force the country's government to withhold its support for the trade deal, which was already backed by the rest of the EU's 28 member nations.

Canada has done everything it could to address any concerns within the EU, and now the ball is in its court, said Pettigrew, who last week was dispatched to meet with Wallonia Minister President Paul Magnette.

"We have worked very hard in the last few months to bring reassurances that we in Canada share those same progressive views," Pettigrew said.

EU nations were scheduled to vote on the deal Tuesday, but that was delayed after Magnette raised objections, saying he needs a few more days.

Pettigrew said the vote could happen as early as Thursday, when EU leaders kick off a two-day summit.

Fear for small Walloon businesses

Wallonia, with a population of 3.5 million, wants more guarantees to protect its farmers and Europe's labour, environmental and consumer standards. It also fears the agreement will allow huge multinationals -- first from Canada, later from the United States, if a similar deal with Washington follows -- that would crush small Walloon enterprises and their way of life.

Proponents say the deal would yield billions in added trade through tariff cuts and other measures to lower barriers to commerce. At the same time, the EU says it will keep in place the region's strong safeguards on social, environmental and labour issues.

Wallonia's rejection left many stumped, even within Belgium, wondering how the small region could have such an impact on a deal between over 500 million EU citizens and 35 million Canadians.

"If we don't agree with Canada, with whom are we going to agree?" asked Slovak Economics Minister Peter Ziga, who chaired Tuesday's meeting.

Former Canadian prime minister Brian Mulroney, no stranger to the complications of trade deals given his role as one of the architects of NAFTA, appeared unfazed by the dispute.

"Every once in a while you run into a hiccup in these things," said Mulroney, who also spoke before the Montreal Board of Trade. "This is a hiccup, but I don't think it's going to derail such an important negotiation."

International Trade Minister Chrystia Freeland said Canada has made significant changes to the deal and remains "cautiously optimistic" that it will receive European approval.

"We're doing everything that we can to support the efforts inside Europe to get this agreement to the finish line, but at the end of the day, as our European partners know, ultimately, this is a European decision," she told reporters in Ottawa.

"I am both hopeful and I also hope that Europe and Europeans can come together to make this decision, which is the right one for Canada and for Europe."

Prime Minister Justin Trudeau is scheduled to fly to Brussels next week to sign the agreement should it be unanimously approved by the EU.

-- With files from The Associated Press