Quebec's construction industry has been hammered with corruption accusations. ((CBC))

There is now unprecedented political pressure on Quebec's premier to call a public inquiry into allegations of corruption and collusion in the construction industry.

The Quebec Federation of Labour, Jean Charest's last remaining ally against an inquiry, bailed on him Wednesday.

'Every day there is some new [report], it's become like a reality show on television, this affair. I think it is time for a full inquiry.' — Michel Arsenault, FTQ president

The FTQ, the province's largest labour group, did an about-face and is not just endorsing calls for an inquiry but is also publicly demanding one and demanding Charest change his tune.

At a news conference in Montreal, FTQ president Michel Arsenault said the "time is ripe, and the time has come" for a wide-ranging probe.

"After the events of the last two years, the discussions we've had among ourselves, the reports we've seen on TV and radio, we've decided together to demand, from the government of Premier Jean Charest, a commission of inquiry," Arsenault said, flanked by Yves Ouellet, president of the FTQ's construction wing, and Lucie Levasseur, CUPE-Quebec president.

"Every day there is some new [report], it's become like a reality show on television, this affair. I think it is time for a full inquiry."

The union leaders said an inquiry should do no less than review public contract tenders and allegations of collusion involving construction firms and elected officials.

Until now, Arsenault had dismissed calls for an inquiry, saying it wouldn't help police investigate individual allegations.

Unionized workers want inquiry

Until late last week, FTQ-Construction repeated its opposition to an inquiry. But union members are tired of the relentless wave of corruption accusations and feel their reputation is tarnished, Ouellet said.

"The FTQ-Construction has always looked out for the interests of its workers and members, and they are telling us that it's time for an enquiry," he said.

Charest has refused to call a probe into accusations of corruption involving the construction industry, politically well-connected businessmen and crime groups such as the Mafia, despite repeated demands from opposition parties.

The premier did order a police investigation last year that was dubbed Operation Marteau (Hammer), and since its inception has said authorities need to do their work without the distraction of a public commission.

Since the investigation began, authorities have carried out several raids and have arrested a handful of people on fraud-related charges.

But Charest has paid a high political price, with polls suggesting the Liberal government has lost significant support over the construction industry scandal.

Opposition parties at the national assembly saluted the FTQ's outing and urged the premier to come to his senses.

With files from The Canadian Press