Wal-Mart Stores Inc. raised the stakes in a fight over its only unionized store in North America, saying it may shut the Quebec outlet unless workers propose a contract the company finds acceptable.

The world’s biggest retailer said a delay in starting talks with the union is hurting business at the 3-year-old store in Jonquiere, 290 miles north of Montreal.

“The Jonquiere store has never made money and its situation has gotten worse in recent months,” said a spokesman for Wal-Mart’s Canadian unit, Andrew Pelletier. “If we are not able to reach a collective agreement that is reasonable and that allows the store to function efficiently and profitably, it’s possible that the store will close.”

The store became only the second Wal-Mart to organize in North America when Quebec’s labor board certified a union local there in August. When butchers at an outlet in Jacksonville, Texas, formed a union in 2000, the company switched to prepackaged meat two weeks later, sending them to other departments and snuffing out the organization drive.

The Jonquiere location employs about 170 people. Last week, workers at a third Wal-Mart store in Quebec filed an application to form a union.

“Wal-Mart has a formula they have to maintain to make money,” said Britt Beemer, chairman of Americas Research Group, a market-research firm in Charleston, S.C. “When worker salaries exceed their ability to pay, Wal-Mart may decide it’s better to close the store than be doomed not to make any money.”

Wal-Mart’s operating margin, or the percentage of sales left after operating costs, was 4.94% in the fiscal year that ended in January, higher than some other discount retailers including Costco Wholesale Corp. and Kmart Holding Corp.

The company said yesterday that it wrote to the United Food and Commercial Workers to demand that a meeting with the Jonquiere local be held October 26 to “begin the labor-relations process.” Marie-Josee Lemieux, president of United Food and Commercial Workers Local 503, said in a telephone interview that the union would meet with Wal-Mart officials as requested and seek to submit a contract proposal by the middle of November.

On September 10, Ms. Lemieux said her goal was to start negotiations by early this month. She wasn’t immediately available to take a follow-up call seeking comment on the delay.

“The unresolved labor situation at the Jonquiere store is proving detrimental to improving the performance,” Wal-Mart said in a Canada NewsWire statement. Wal-Mart’s earlier attempts to hamper the organization drive in Quebec failed.

The Bentonville, Ark.-based company first argued that more workers at the Jonquiere store should have been included in the vote on whether to unionize it. Wal-Mart then drew a rebuke from Quebec’s labor board in September over allegations that it was interfering with the union’s efforts to sign up employees at a store in the Montreal suburb of Brossard.

Wal-Mart’s Mr. Pelletier said the union’s exclusion of about 30 hourly workers at the Jonquiere store is creating a “fractured” workplace that’s hindering sales. Ms. Lemieux disputed his assessment.

“I met with two groups of Wal-Mart employees in Jonquiere yesterday and there was certainly no discomfort on their part,” she said. “People understand how the bargaining process works and they’re not concerned.”

Ms. Lemieux said sales in Jonquiere may have slowed in the past year because Wal-Mart opened a store in the town of Alma, about 25 miles away.

Wal-Mart operates 44 stores in Quebec, Canada’s second-most populous province after Ontario. It has a total of 234 Wal-Mart and six Sam’s Club stores countrywide. The company’s shares fell 37 cents to $52.55 in New York Stock Exchange composite trading.