Quebec's municipal affairs minister said Wednesday that she's very concerned about a series of scandals at Montreal city hall.

Nathalie Normandeau told reporters in Quebec City that she wants the Surete du Quebec to work quickly to get to the bottom of the problems that range from alleged corruption and extortion to fraud.

The latest alleged malfeasance emerged Tuesday involving the project to replace the roof at City Hall.

La Presse reported that a mobster asked contractor Paul Sauve to pay off two city councillors to guarantee the roof contract.

Sauve says he never paid the bribe.

Defends his team

The two councillors named in the story are Sammy Forcillo and Cosmo Maciocia, both of whom are part of Mayor Gerald Tremblay's Union Montreal team.

The mayor says he stands behind his councillors.

"They still have my confidence and you can ask them the question," Tremblay told reporters in St. Henri on Tuesday evening.

Unprecedented corruption, says Harel

Vision Montreal Leader Louis Harel, who will try to unseat Tremblay in an election this fall, said city hall has never seen such corruption.

"It's the sixth police investigation," said Harel.

"I don't know of any other time in the history of Montreal that we've had police investigations like we are witnessing now."

SQ wants public's help

In the meantime, the SQ is reminding people that it has an ongoing investigation into the problems of organized crime in the construction business.

The police force says people working in the industry face threats, intimidation and violence.

The SQ tip line is 1-800-654-4264.

Any information will be kept confidential and anonymous.