Radio-Canada, CBC's French-language service, was scheduled to air a documentary later Friday in which security guards say they had been hired around the time Wal-Mart decided to close the store in Jonquiere, about 155 miles north of Quebec City.

Wal-Mart, the world's largest retailer, cited financial reasons for the closing. Union activists had claimed the Arkansas-based company was shutting them down because they nearly won the first-ever union contract from the retailer.

The closure announcement provoked angry demonstrations and bomb threats were called in against the two Canadian Wal-Mart stores in Quebec.

Wal-Mart closed the store in April, not long after the 200 workers received union accreditation, but before they could sign a collective agreement.

According to excerpts from the TV documentary, union leaders and workers sympathetic to the drive were targeted by undercover security guards. Spying on union leaders or sympathizers is illegal under the Quebec Labor Code.

One former guard said he patrolled the store in civilian clothes, watching employees. Another said the store's surveillance cameras were used to follow certain employees.

The guards said their tasks did not correspond to the normal duties of security.

Wal-Mart Canada president and CEO Mario Pilozzi denied the allegations.

"No, we wouldn't tolerate the situation you mentioned," Pilozzi told Radio-Canada. "No idea about what you're talking about."

Andrew Pelletier, a spokesman for Wal-Mart Canada headquarters in Mississauga, just outside of Toronto, also denied the allegations.

"There was absolutely no spying done; we would not support that," he told The Associated Press, adding private security guards were hired to protect its customers and employees. "Prior to the closure of that store, there was a volatile situation with the union and we wanted to make sure that safety and security were respected."