How will Joe Oliver, Olivia Chow navigate Toronto's shifting electoral tide?

If Torontonians think their city is the centre of the universe, federal politicians will do little to dissuade them from that notion as election day draws near, as Canada's largest city could also be the site of some of the country's fiercest electoral battles.

Finance Minister Joe Oliver finally found out who his opponent would be this week in his riding of Eglinton–Lawrence, after lawyer Marco Mendicino beat out former Conservative MP Eve Adams for the Liberal nomination.

But the opposition parties will have other big names on the ballot in Toronto, including former police chief Bill Blair for the Liberals and a return by Olivia Chow to the federal scene for the NDP.

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• Tory defector Eve Adams loses Liberal nomination race

And this is just within Toronto itself. More seats will be up for grabs in the wider Greater Toronto Area, but the city proper will also be a focus of each party's election campaign.

The Liberals narrowly won the popular vote in Toronto in 2011, taking 34.7 per cent of the vote to the Conservatives' 31 per cent and the NDP's 30.6 per cent. But the party came up third in the seat count, winning six of Toronto's seats while the Conservatives and NDP each won eight.

That represented a major shift from the 2008 election, when the Liberals won 20 seats in Toronto, leaving only two for the NDP. The eight seats the Conservatives won in Toronto represented one-third of the party's net seat gains nationwide.

Conservatives in trouble in T.O.

But Toronto could be set for another swing. Based on the latest polls, the Conservatives have dropped about nine points in Ontario since 2011. The Liberals have picked up five points and the NDP has gained two. If these trends carry through to Toronto, the Tories stand to lose out.

Three of the 15 new seats that have been granted to Ontario are in Toronto, boosting the city's electoral heft from 22 to 25 seats (more than six provinces have). Considering current polling levels in the province, the Liberals are poised to capture 11 to 17 seats in the city, with the New Democrats winning between eight and 11. The Conservatives could be reduced to three seats or less.

All three of those seats should be Liberal-Conservative contests that the Tories are at risk of losing. And while that, on paper, includes Joe Oliver's seat, sitting finance ministers have proven very hard to defeat.

But the Liberals look well placed to win their seats back in York, Etobicoke and Don Valley while the New Democrats could make gains in Scarborough and the downtown core. Without a big shift in voting intentions, seat gains for the Conservatives appear to be out of the question.

Or are they?

However, province-wide polling is a very crude tool for gauging the state of the race in Toronto. Unfortunately, public polling within the city has been rare.

The most recent national survey from Mainstreet Research did include a breakdown for Toronto, which suggested the parties have hardly budged since 2011. But considering the margin of error of just under seven points among decided voters, and the lack of other sub-regional polling to put the numbers into context, it is difficult to draw any definitive conclusions.

More broadly, the Liberals have tended to poll between 35 and 45 per cent in the city since the last election, with the Conservatives between 25 and 35 per cent and the NDP between 21 and 31 per cent. These numbers have ebbed and flowed without any clear pattern, likely in large part due to the smaller sample sizes. But if the Conservatives have held their own in Toronto while losing support in the rest of the province, they could still be in play in as many as 10 ridings in the city.

The more frequent provincial political polls, for what they are worth for hinting at federal politics, have put Kathleen Wynne's Liberals at around 36 per cent, Andrea Horwath's NDP at 32 per cent and Patrick Brown's Progressive Conservatives at 26 per cent in Toronto since mid-May. At the very least, this would seem to suggest that Toronto is not swinging in a manner wildly different from the rest of the province.

Considering recent trends, that would be good news for someone like Chow or the group of former Liberal MPs defeated in 2011 looking for a comeback in Toronto in 2015.

Oliver's status as minister of finance can help him survive a local Conservative cull, but his re-election is far from assured. And if the Tories' numbers don't improve in Toronto, he could find himself representing a lonely blue dot in a red and orange city.

CBC's Poll Tracker aggregates all publicly released polls, weighing them by sample size, date and the polling firm's accuracy record. Upper and lower ranges are based on how polls have performed in other recent elections. The seat projection model makes individual projections for all ridings in the country, based on regional shifts in support since the 2011 election and taking into account other factors such as incumbency. The projections are subject to the margins of error of the opinion polls included in the model, as well as the unpredictable nature of politics at the riding level. The polls included in the model vary in size, date and method, and have not been individually verified by the CBC. You can read the full methodology here.

The questions asked in Mainstreet poll was as follows: "If the federal election were today, which party would you support?"