Two projected front-runners in the Mississauga mayoralty race – the first real one in Canada's sixth-largest city since Hazel McCallion took the reins three decades ago – are gearing up their campaign machinery, although neither Bonnie Crombie nor Steve Mahoney have officially declared their candidacy.

Perhaps the biggest surprise is that former Liberal MP Carolyn Parrish, a long-time critic of Ms. McCallion, is not among them. Ms. Parrish, long-rumoured as a potential candidate, confirmed to The Globe and Mail she is not interested in the job and instead plans to run for a council seat in Ward 5 (the one she lost by 241 votes to Ms. Crombie in a 2011 by-election).

Ms. Crombie, a former Liberal MP, and Mr. Mahoney, a former councillor, federal cabinet minister and Liberal MPP, both say they are strongly considering the city's top job.

Story continues below advertisement

Ms. McCallion has survived three conflict of interest charges, the most recent one this past year, and has been re-elected time and again with strong mandates (in 2006, she captured 91 per cent of the vote). Many assumed the 92-year-old "Hurricane Hazel" would never retire, but she has said this term, her 12th, is her last.

The city's next mayor will no doubt face constant comparisons to Ms. McCallion: She oversaw the growth of Mississauga from a mostly rural municipality to a city of 752,000, attracting hundreds of major corporations, who in turn brought millions in development dollars. But the new mayor will also inherit major challenges: Mississauga is nearly built out and the once-plentiful development reserves have dried up. Two of the city's biggest costs in the coming years will be repairing crumbling infrastructure (the annual infrastructure deficit is about $80-million) and building a planned light-rail transit line on Hurontario Street. Ms. McCallion and other local politicians have said the city cannot lean on property taxes alone to keep the city moving forward.

"Whoever takes that job after Hazel is going to go through four years of hell," Ms. Parrish said.

Councillor Ron Starr said potential candidates are biding their time because they're still weighing the challenges of the job, but also because the campaign will prove to be an expensive one.

"Nobody's ever run a mayoralty campaign in Mississauga," he said. "It's going to be a minimum $500,000 or $750,000 campaign. It's not like Hazel, who would run it on $85 because she bought coffee."

According to a source, a December discussion between Mr. Starr and Mr. Mahoney led to the former deciding against running in order to support Mr. Mahoney's campaign. Mr. Mahoney, who served in Jean Chrétien's cabinet, did not plan on seeking the mayor's seat until he connected with Mr. Starr, a close friend, before Christmas. Mr. Starr encouraged him to run because he stood a better chance of beating Ms. Crombie, the source said.

In an interview, Mr. Starr said he himself was "90 per cent of the way to making a decision" and said if he does not run for mayor, he will seek re-election in his ward. In an interview, Mr. Starr said he'd had a conversation with someone in which that person told him, "If you don't run [for mayor], I'm running."

Story continues below advertisement

Mr. Starr said the city's new mayor will have to work closely with provincial and federal partners, something he sees as a natural strength of Mr. Mahoney's. "That's why I think a guy like Steve, now, he does have a lot of those interactions...that a city can benefit from."

According to a source, Ms. Crombie met Mr. Mahoney for lunch in December and shared her intention to run and asked if he would support her. Mr. Mahoney was non-committal, the source said.

Ms. Crombie said she is consulting with the community about whether to run and "not willing to make a commitment just yet."

If Mr. Mahoney were elected mayor, it would be his first return to city hall in a quarter-century. He was elected as a councillor in 1978, the same year Ms. McCallion became mayor. According to a source, before Mr. Mahoney left city hall for Queen's Park in 1987, he met with the mayor to let her know the Liberal party wanted him to run for provincial office but that he was interested in becoming Mississauga's mayor one day.

The conversation was short – Ms. McCallion apparently told Mr. Mahoney that good people were needed at the province, the source said. That year, Mr. Mahoney successfully ran in the provincial election. After losing his seat in 1995, he made the switch to federal politics in 1997 and was an ardent supporter of Mr. Chrétien. After Mr. Chrétien was replaced by Paul Martin as Liberal leader, Mr. Mahoney was kicked to the backbenches. He is currently in the middle of a contract as CEO of the Radiation Safety Institute of Canada.

Sources say Mr. Mahoney likely won't register to run as mayor until the spring.

Story continues below advertisement

"I have been approached by a lot of people that are asking me to do this," he said in an interview. "I have a commitment to my current employer and I have made no decisions yet."

Ms. McCallion herself has stopped short of endorsing any one of the rumoured candidates to replace her, but is known to be close friends with Ms. Crombie.

"We have talked about it a little bit. She is supportive. I support her legacy and support the things she's done. I think she'd like to see the legacy continue," Ms. Crombie said.

The Contenders

Steve Mahoney, 66, has been in politics for more than half his life, serving at all three levels of government. He was elected to Mississauga council in 1978 and spent nine years there before making the switch to provincial politics as a Liberal MPP representing Mississauga West.

He ran for leadership of the provincial Liberals in 1992 but only made it to the second ballot. He lost his seat in 1995. In 1997, he ran for the federal seat in the same constituency and won. A Jean Chrétien loyalist, Mr. Mahoney was appointed secretary of state for crown corporations in 2003– a portfolio he lost just eight months later when Paul Martin became Prime Minister.

Story continues below advertisement

In 2003, Mr. Mahoney's riding was eliminated due to redistribution, which set the stage for a very ugly battle with Carolyn Parrish, a Paul Martin supporter, for the Liberal nomination in Mississauga-Erindale. The nomination fight was characterized by vicious personal attacks and the night Ms. Parrish clinched her victory, Mr. Mahoney said, "No power on Earth could make me congratulate her."

He spent six years as the chair of the Workplace Safety and Insurance Board, a role he says was "the most political" job he's ever had. In his last year with the WSIB, he was diagnosed with cancer on his tongue. After several months of intense treatment, he was declared "cancer-free." Since September, he has been CEO of the Radiation Safety Institute of Canada, which monitors the safety of radiation exposure.

Bonnie Crombie, 53, is a Mississauga city councillor and former Liberal MP. She entered politics in 2008, when she ran for a federal seat in Mississauga-Streetsville and won with 46 per cent of the vote. Former Liberal leader Michael Ignatieff appointed her shadow minister for crown corporations. In May, 2011, she lost her seat to Conservative Brad Butt and set her sights on the city council seat of Eve Adams, who abandoned it to become a Conservative MP.

What might have otherwise been a quiet by-election campaign for Ward 5 grew heated when ex-Liberal MP Carolyn Parrish, Mayor Hazel McCallion's chief opponent, entered the race in an attempt to get back in to city council after having lost her seat in the 2010 election. It has been reported that Mayor Hazel McCallion encouraged Ms. Crombie on multiple occasions to run for council. Ms. Crombie later won a by-election for Ward 5 by 241 votes against ex-Liberal MP Carolyn Parrish. During her victory party, she said, "The residents chose someone who would support council and support the mayor."

Before entering politics, she worked and volunteered with a range of non-profits: she served as fundraising chair of the Ontario Brain Injury Association and was a board member with Arts Umbrella, a non-profit arts education centre. According to her official biography, Ms. Crombie co-founded Cargo Cosmetics, a company that started up in Toronto in 1996 and grew into a multi-million-dollar corporation.

Her husband, Brian Crombie, heads up Crombie Capital Partners, a financial consulting firm, and is chief financial officer of PurGenesis Technologies. In 2009, he was ordered to pay $300,000 for violating the province's securities law when he was chief financial officer of drug company Biovail Corp.