Gérald Tremblay (left), Louise Harel (centre) and Richard Bergeron fought a tight race for mayor in Montreal. (CBC)Gérald Tremblay won a third straight term as mayor of Montreal despite a campaign dominated by allegations of corruption involving the Mob and construction companies.

Tremblay, who leads the Union Montréal municipal party, beat rivals Louise Harel and Richard Bergeron in a tight race Sunday.

The mayor said he is "conscious that the confidence of Montrealers has been put to the test."

"The citizens want change and we will incarnate that change," Tremblay said.

Tremblay won with less than 40 per cent of the popular vote to secure his third consecutive mandate as mayor of Canada's second-biggest city.

The 67-year-old mayor defeated former Parti Québécois minister Louise Harel, who ran as leader of municipal party Vision Montréal.

Tremblay also came out ahead of dark horse candidate Richard Bergeron, who led upstart party Projet Montréal.

Tremblay prevailed despite his administration being dogged by scandals — from the city's water meter contract to construction contract-tender irregularities.

Mayor Gerald Tremblay, with wife Suzanne Tailleur, says his challenge is to regain the confidence of all Montrealers. (CBC) He was forced to cancel the $355 million water-meter contract mid-campaign after the city's auditor general released a damning report about irregularities in how the project was managed.

Tremblay said he recognized citizens want "Montreal to be an exemplary model ... [of] integrity."

He said his challenge would be to "regain the confidence of all Montrealers."

Because of legislative changes following the last municipal election, Tremblay will now also take on the responsibility of being mayor of the Ville-Marie borough.

Rivals claim huge strides

Reacting to her first defeat in a political career that has spanned nearly three decades, Vision Montréal Leader Louise Harel promised to continue her fight "to put an end to corruption, collusion, and costly sub-contracting."

"I would have liked Montrealers to choose change, but let's understand that they didn't vote for the status quo, because two-thirds of voters didn't choose the status quo," Harel told supporters gathered at a downtown auditorium on Saint-Denis Street.

"Like all of you here tonight, I wished here tonight that Montrealers would choose the change we proposed. But electors chose otherwise, and we accept their choice," she continued in English. During the campaign, the former Parti Quebecois minister was criticized for her limited ability to speak in English.

Harel said she was extremely proud that her party led what she called a "clean campaign with popular financing" by refusing to accept anonymous donations.

During the campaign Harel promised to centralize city services including garbage collection, snow removal, and road work. She also promised to freeze taxes and public transit rates for her first year in office, a plan Tremblay called unrealistic.

Projet Montréal Leader Richard Bergeron told his supporters he was proud of the ground they gained during the campaign.

"We were nothing five years ago, and we obtained 25 per cent of the vote, and many of our candidates will be elected for Projet Montreal," he said to loud applause.

Bergeron congratulated Tremblay for his victory, saying the population has spoken, and "it's the population's choice."