Both of Montreal's opposition parties are looking for more clout at city hall and hope Union Montréal will open up its executive committee to be run as a coalition.
Projet Montréal leader Richard Bergeron said working together would help repair what has been broken in the last few years.
Union Montréal member Marvin Rotrand said the parties should set their priorities before moving too quickly.
"At this point, I think what is a first priority is to put a new mayor into office," said Rotrand, who also added that his party was willing to collaborate.
"I'm not asking them to vote for everything we put forward," said Rotrand. "But we're going to try to find common ground to move forward with dossiers and ensure people good service."
Westmount Mayor Peter Trent believes a coalition at city hall's executive committee could give voters more confidence in the administration.
Quebec's minister responsible for Montreal Jean-François Lisée said the province will work with the city to help get things on track and restore trust among citizens.
Coalition Avenir Québec leader François Legault said though Tremblay may be gone, his party and his administration remain in power.
"It's very important that the government take action," he said. "And I think they should consider very seriously putting an independent inspector in Montreal to make sure that the contracts that will be [awarded] in the next few days, few weeks, few months that they are given at a reasonable price."
Filling the void
Montreal has not been without an elected mayor since the 1940s. Since Tremblay stepped down with less than a year left in his mandate, there will be no by-election to replace him.
Within the next 30 days, council will have to select an interim mayor to lead the city until a municipal election on Nov. 3, 2013. The decision will be made by secret ballot.
In the meantime, Lachine city councillor Jane Cowell-Poitras will be filling in as interim mayor.
"I realize that this is a difficult period," said Cowell-Poitras. "I am there to provide comfort. I'm a mother before anything else and I really feel that it's my job to make sure that people know that the city of Montreal is continuing to work. Everything is functioning normally and we are all doing our best."
Opposition parties agree with Cowell-Poitras but say restoring the population's faith in city hall will only be achieved if all parties work together.
"It's very important to have a very representative group to run the city and to re-establish the trust in the administration," said Louise Harel, leader of Vision Montréal.
Harel and Bergeron both said they would run for the top job during the next municipal election.