By Paul Vieira and William Mauldin 

The Obama administration on Wednesday launched a trade challenge against Canada's treatment of U.S. wines, arguing the rules in place undermine fair competition.

The row emerges at a time of growing economic unease among Canadian officials over the economic ramifications President-elect Donald Trump and his eventual changes to trade policy might have on growth.

U.S. Trade Representative Michael Froman said the complaint filed with the World Trade Organization focuses on regulations in the Canadian province of British Columbia. Mr. Froman said British Columbia's rules "effectively deny" the sale of U.S. wine on grocery-store shelves, and as a result gives that province's winemakers an unfair advantage.

The rules as set out by British Columbia "appear to breach Canada's commitments as a WTO member," Mr. Froman said. "Canada and all Canadian provinces...must play by the rules."

A spokesman for Canada's foreign minister said it is aware of the complaint and would give it serious consideration.

For weeks now, Canadian Prime Minister Justin Trudeau has vowed to work with the incoming Trump administration about changes Mr. Trump and his team want to make to the North American Free Trade Agreement, or Nafta. Any change to Nafta would affect Canada, but most of the Trump team's public pressure to date has been on Mexico and its growing auto industry.

The new administration's pick for commerce secretary, Wilbur Ross, on Wednesday emphasized the "rules of origin" for the automobile industry as a focus of trade negotiations. Tighter rules of origin could force auto makers to produce more parts in North America.

Mr. Ross said it is "not an accident" that the Mexican peso and even the Canadian dollar have come under pressure since Mr. Trump was elected, because it alerted investors that changes to trade policy are coming.

The case over wine also underscores how trade relations between Ottawa and Washington have deteriorated since the two countries signed the 12-nation Trans-Pacific Partnership, a major trade agreement that failed to win a vote in the U.S. Congress after Mr. Trump was elected in November. Two-way trade between the U.S. and Canada is among the largest trading relationships in the world, totaling $474.4 billion during the first three quarters of 2016, according to data from the U.S. Bureau of Economic Analysis.

U.S. lawmakers have complained about Canadian softwood lumber policy, part of a longstanding dispute between the two countries. Efforts by Mr. Trudeau and President Barack Obama to find a resolution over lumber trade have fallen short. The Commerce Department and International Trade Commission are now investigating Canadian lumber imports, and the commission issued a preliminary finding earlier this month against Canada. U.S. lawmakers have also complained about Canada's support for its dairy industry, which makes U.S. products less competitive there.

Earlier Wednesday, Bank of Canada Gov. Stephen Poloz warned any material change in U.S. trade policy could bring a potential negative shock to the Canadian economy. Canada's economy is relying on nonenergy exports to help lead a recovery following a deep hit from lower commodity prices.

"While the precise trade policy measures to be taken by the incoming U.S. administration remain to be determined, the protectionist tilt is already evident," the central bank said in an updated economic outlook, released at same time as a decision to keep its policy rate unchanged at 0.5%.

Negative effects for Canada are possible if Washington makes material changes to trade policy, the central bank said. As a result, the Bank of Canada's current economic outlook is "more conditional than usual," Mr. Poloz told reporters at a press conference.

Write to Paul Vieira at paul.vieira@wsj.com and William Mauldin at william.mauldin@wsj.com

(END) Dow Jones Newswires

January 18, 2017 14:50 ET (19:50 GMT)

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