The FTQ union as well as some of its high-ranking officials had filed the request to stop the inquiry from hearing the taped conversations, which were recorded as part of a police investigation into organized crime. The taped conversations did not result in criminal charges being laid.
In a decision Monday, corruption inquiry head France Charbonneau remarked that the telephone conversations could prove useful in helping witnesses who can't remember details on the stand.
The ruling said the inquiry is committed to using only parts of the conversations related to professional functions and won't extend to discussions involving private lives.
While inquiry participants have the right to privacy, it's not an absolute right and the definition of "privacy" depends greatly on the context of the information, the ruling said.
"We must find a balance between private interests, the right to respect for privacy and the public interest is the search for truth and public information related to the mandate of the inquiry," the commission wrote.
A lawyer for the Fonds de solidarite FTQ, the big union venture-capital fund, had argued the inquiry had no right to play those wiretaps.
Jean-Claude Hebert said Monday that he would consult with his clients before deciding how to proceed.
The motion was on behalf of two people including Michel Arsenault, who's not only the union president but also the president of the board of the investment fund.
They said the recordings were of private conversations and, while making their argument, cited the U.S. Edward Snowden case while discussing privacy concerns.
The recordings were made during the provincial police's Operation Diligence — which was examining organized crime's infiltration into the legitimate economy, with a special focus on the masonry industry. Investigators stumbled upon phone conversations between union leaders and the Fonds de solidarite.
The FTQ lawyers had filed a motion arguing that the broadcast of surreptitious recordings violates the Article 193 of the Criminal Code, as well as sections 7 and 8 of the Charter of Rights and Freedoms.
The fund has more than $9 billion in net assets and is the largest of its kind in the country.
It would feel the biggest impact from a move, announced in the last federal budget, to phase out a tax credit for union-backed mutual funds.
The Harper government argues that the credit leads to inefficient investment decisions at a cost of $140 million a year to the federal treasury.
The role of construction unions, and the FTQ fund, is expected to be a major focus of the Quebec corruption inquiry this fall.
On Monday, a witness described how his FTQ union used its former power to pick workers to advance its own interests on construction sites. The law was revoked under the Charest Liberals.
Businesses that got along well with union bosses could get the best workers, and those who didn't would get the "bottom of the barrel" workers which would slow down a project, he testified.
Another witness Monday, the former director-general of a masonry business owners' association, said she was intimidated a dozen times after people found out she planned to testify at the inquiry.
Stephanie Berard said a car would be parked outside her house, lights blaring into her window. She received a bluntly worded warning on her home voicemail not to testify.
She was eventually fired.