MONTREAL - Criminal charges against a former high-ranking union official and allegations of intimidation of workers vaulted Quebec's much-maligned construction industry back into the spotlight Thursday.

This time, news that Jocelyn Dupuis was being sought on fraud and forgery charges was enough to prompt renewed calls for a public inquiry into the industry.

The warrant issued for his arrest is related to crimes allegedly committed in 2007 and 2008 while Dupuis was at the helm of the Quebec Federation of Labour's influential construction wing.

Dupuis, 55, was the organization's director-general for 11 years before being forced to resign in 2008 after it was revealed he'd managed to incur $125,000 worth of expenses in a six-month period.

Dupuis, who is reportedly on vacation in the United States, is facing three charges -- one each of fraud, forging documents and counselling another person to commit the forging of a document.

That alleged third offence wasn't carried out.

The Crown alleges Dupuis defrauded the construction wing of more than $5,000 between Dec. 2, 2007, and Nov. 11, 2008.

He is also accused of producing 208 false documents related to 39 weekly expense accounts and 169 restaurant bills.

The Quebec Federation of Labour is the largest union in the province and its construction wing represents about 70,000 workers.

Provincial police declined to comment Thursday. But politicians took the opportunity to assail the government in a particularly raucous question period at the legislature.

"I hope it's only a small portion of this industrial sector that is corrupt," Opposition Leader Pauline Marois told a news conference in Quebec City.

"But actually the facts seem to indicate there is an infection somewhere. How bad it is, we don't know and that's what a commission of inquiry will allow us to find out."

The Liberals, as they have for months, dismissed any notion of a public inquiry and put their faith in an ongoing police investigation.

In a statement, the construction wing said its current leadership handed over all the documents and bills to police in March 2009.

It reiterated that the current union administration faces no charges.

News of the warrant against Dupuis comes as his former union faces allegations of intimidation and discrimination on Quebec's North Shore.

An investigative report by Radio-Canada documented dozens of instances of thuggish behaviour by a union representative and has prompted Quebec to call on police to investigate the allegations.

CBC's French service has reported that a climate of intimidation and violence exists on worksites controlled by the Quebec Federation of Labour.

That, too, served only to provide more fodder for the opposition parties.

"In the last months we've heard about allegations of collusion, fixed offers, generalized under-the-table work, inflated billing and now cases of intimidation," said PQ public security critic Bertrand St-Arnaud.

"What more is it going to take? Are you waiting for a rampage on a construction site?"

Quebec announced last fall it was creating a special squad and launching Operation Hammer, a widespread investigation into allegations of corruption in the construction industry.

The squad conducted a series of visits and raids over the past few months, but no arrests have yet been made.

The province has also introduced new legislation to tighten the financing of political parties and the awarding of public contracts.