Angered by news of alleged collusion and corruption in Montreal city services, unions demonstrated in front of city hall Tuesday, saying they’re being forced to pay the price.

Last week the Liberals tabled Bill 3, a proposal to reform public pensions and set up a framework for 18 months of negotiations and, if necessary, six months of arbitration.

Many unions have called the tabling of Bill 3 and the proposals to reform public pensions a "declaration of war," but a united front of mayors from across Quebec are calling on union leaders to tone down the rhetoric.

Meantime, unions blame corruption for pension plan shortfalls. The Montreal auditor general’s report released Monday evening revealed possible bid rigging has led to inflated costs for services such as garbage collection and recycling, as well as snow removal.

The revelations led to a large 2 p.m. protest that included fire trucks, police cars and motorcycles parked outside city hall and turned on their sirens all at once.

Protesters were joined with hundreds of off-duty officers and city workers concerns about pension cuts. Union organizers said it was not an illegal protest, but that they were simply taking a 15-minute break.

Unions argue there is a direct link between this kind of municipal mismanagement and the current $3.9 billion pension fund deficit.

Quebec's municipalities are seeking to cut deficits by reforming the pension plans to include higher employee contributions.

Unions say it isn't fair they are expected to pay the price for years of alleged inflated contracts.

Marc Ranger, a spokesperson for a coalition of the unions fighting the reforms, said the auditor general report confirms what they already knew.

“We’re shocked at the same time, because we’ve been saying for the last few years that in the private companies in Montreal, there’s a lot of collusion and corruption with snow removal and waste, and this is the most important area where the money goes. We’re happy to see the auditor general reporting on this,” he said.

"We hear about corruption, collusion, so we're asking (Mayor Denis) Coderre to take care of that and leave us our working conditions that we did bargain for."

The unions say say this sort of collusion could not happen if the city didn't contract out to private firms and hired in-house instead.

They also want to see the officials connected to these contracts take responsibility.

While the report shows a likelihood of bid rigging, Auditor General Jacques Bergeron said it's just an initial step.

"We are not UPAC or police," he said. "We can't do more than raise the flag."

City officials said they welcome the recommendations made by the auditor general, and plan to send the audit to the inspector general.

Union organizers say the city can expect more protests throughout the summer.