MONTREAL - Michael Ignatieff has become the latest politician to brush off calls for a public inquiry into an alleged corruption scheme involving politicians, construction companies and the Mafia.

The Liberal leader says the Quebec government has done a good job appointing a special police unit to probe allegations of a massive scam, and that Ottawa should only step in if there's evidence of federal involvement.

The federal government is already spending billions on the most expensive construction program in Canadian history, and organized-crime experts note that criminal collusion exists in many places where the Mafia operates.

But it's Quebec that has been rocked by reports of construction companies working together to drive up the price tag on public-works projects, funding political parties with cash, and sharing their profits with the Mafia.

Widespread calls for inquiry

A recent poll suggested overwhelming support in the province for an inquiry, the Facebook website is being flooded with calls for one, and opposition politicians at the provincial and municipal levels have demanded one.

But the federal Liberals have joined the governing Conservatives, the mayor of Montreal, and the Quebec provincial government in rebuffing talk of an inquiry.

"This is a matter that the Quebec government is handling well and it's a matter for police authorities and they're handling it well,'' Ignatieff told reporters during a stop in Montreal.

"Should there be federal implication, at that point we can get federal authorities involved, but at the moment, I think the government of (Premier Jean) Charest is doing its homework.''

Denial

A prominent expert on the Italian mob believes Canada has no interest in fighting organized crime, in part, because it's afraid of how entrenched it's become in legitimate society -- something he said is particularly true in Quebec.

"Nobody in Canada wants to address the corporate side of organized crime -- that the Mafia invests money in legitimate business, are funding political campaigns of candidates,'' Antonio Nicaso said in an interview.

"I don't think that's something that we want to uncover.''

Canada is currently undergoing inquiries into a Taser death and a police shooting, and federal politics was monopolized for months by an inquiry into a comparatively tiny thing called the sponsorship program.

Why not a probe into an alleged multibillion-dollar scam sucking money from the public treasury and into mobsters' pockets?

Nicaso offered an explanation for why politicians would shy away from a full probe -- a reaction he predicted when the scandal first erupted: "They are scared that they will find their people involved in this business.

"To me, that's why they don't want to address the issue.''