With the Liberals and Conservatives locked in a virtual dead heat in national polls, the race is "too close to call" in three prominent local ridings.

A new poll conducted exclusively for Postmedia by Mainstreet on Oct. 4 shows the sprawling rural West Quebec riding of Pontiac, as well as newly formed Ottawa ridings of Kanata-Carleton and Nepean "going down to the wire," according to Mainstreet pollster Quito Maggi.

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Pontiac, long considered a bellwether riding -- with West Quebec voters electing a candidate from the winning party in each election from 1980 to 2011 -- strayed from that trend when rookie NDP candidate Mathieu Ravignat unseated then-Minister of Foreign Affairs Lawrence Cannon in the province's so-called "Orange Crush."

Now, Ravignat finds himself fending off Liberal challenger Will Amos, with only a single point separating the two in the polls.

The Liberals finished a distant third in 2011 with less than 13% of the final vote tally, but now it's the Conservatives trailing the two-horse race, with Tory Benjamin Woodman polling at 17%, while Ravignat and the NDP are at 28% and Liberal Amos hot on his heels at 27%.

"It's clear that voters in Pontiac want change, but haven't made a clear decision as to whether the NDP or Liberals represent the best shift in direction," said Maggi, calling Pontiac "a riding worth watching."

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Liberals have also been making a surge in the traditionally staunch Conservative territory of Kanata-Carleton.

While the new riding may have redrawn its borders, the Tory stronghold made for an easy win for Gordon O'Connor, who enjoyed at least 56% of the vote in each of the past three elections.

But with the 76-year-old O'Connor not seeking re-election, it's up to Walter Pamic to keep the Conservative streak alive.

And while it may have seemed unthinkable in a true blue riding (one that has been represented provincially by MPP Jack MacLaren or predecessor Norm Sterling since the mid-'70s) Liberal candidate Karen McCrimmon is mounting a charge.

Pamic was dismissive when presented with the results of a mid-September poll -- conducted by left-leaning Ecology Ottawa and LeadNow -- that showed Conservative support at 44% with Liberals at 37%.

But while fresh data shows Conservative support virtually unchanged at 45%, the Liberals have closed to within two points at 43%. And with large numbers of respondents saying they are "certain to vote" -- voter turnout was nearly 73% last time out -- Mainstreet calls Kanata-Carleton "an exciting race to watch."

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Just like their neighbours in Kanata, "voters in Nepean are nearly evenly split between the two leading parties," Maggi concluded.

While Pierre Poilievre is a shoo-in for the neighbouring seat in Carleton (formerly Nepean-Carleton), his former aide Andy Wang is not enjoying quite the same landslide of support in the splinter riding of Nepean.

At 42%, Liberal candidate Chandra Arya sits a sole point ahead of Wang's 41% -- well within the margin of error -- while NDP candidate Sean Devine lags well behind with 13%.

"As in Kanata-Carleton, large numbers of Liberal and Conservative supporters say they're 'certain to vote,' making Nepean another contest to follow on election night.

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And just like in Kanata-Carleton, the departure of a long-serving Cabinet minister has left a void that's been challenging for Conservative successors to fill in Ottawa West-Nepean.

While earlier polls were less certain of the outcome in John Biard's former Tory stronghold, Mainstreet is now predicting the old blue riding will turn red on Oct. 19, with Liberal Anita Vandenbeld now leading Conservative Abdul Abdi by nearly 20 points in the latest poll.

Vandenbeld leads among decided and leaning voters with 47% support, while Abdi is a distant second with 29%, and NDP candidate Marlene Riviere stands at 20%.

"Vandenbeld should be feeling confident as we approach election day," said Maggi, "especially given her commanding lead (54%) among voters aged 50 to 64."

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Despite an "energetic" campaign run by Liberal challenger Catherine McKenna, Paul Dewar appears to be safe in Ottawa-Centre. But there's still a "wild card" in the race, according to the Mainstreet poll.

The popular NDP incumbent leads McKenna 42% to 30% among decided and leaning voters, while Conservative challenger Damian Konstantinakos lags behind at 22%.

However, only half of each party's supporters described their support as "strong" in the telephone poll.

"If the NDP continues to decline, this seat could be in play," said Maggi. "But for now, Dewar's popularity is holding."

Mainstreet surveyed a random sample of 673 Pontiac residents, 661 Ottawa-Centre residents, 685 Ottawa West-Nepean residents, 630 Kanata-Carleton residents and 655 Nepean residents on Oct. 4, surveying a mix of landlines and cellphones.

Twitter: @OttSunHelmer