Liberal Leader Michael Ignatieff says the Quebec government has done a good job appointing a special police unit to probe allegations of a massive scam. (CBC)

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

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

With government spending billions on the most expensive construction program in Canadian history, organized-crime experts say criminal collusion exists in many places where the Mafia operates.

But it's Quebec that has been rocked by reports 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.

'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, organized crime expert

A recent poll suggested overwhelming support in the province for an inquiry, 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 implications, 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."

Organize crime entrenched in society

Antonio Nicaso, an 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 Nicaso 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," Nicaso said in an interview.

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

Scott Hennig of the Canadian Taxpayers' Federation supports calls from the Parti Québécois for a public inquiry but believes federal politicians are justified in staying out of what appears, so far, to be a strictly local matter.

Public Safety Minister Peter Van Loan has said there's been no evidence of federal stimulus money winding up with the Mob. However, he cautioned that Ottawa doesn't dish out the bucks to construction companies itself.

Infrastructure cash is transferred through federal-provincial arrangements with municipalities that are subject to provincial laws for tendering, he said.

So far, only opposition politicians in Quebec have demanded an inquiry.

The Parti Québécois is expected to present a non-confidence motion against the governing Liberals over the corruption scandal. Since the Liberals hold a majority in the legislature, the motion appears doomed to fail.