Toronto City Councillor Adam Vaughan is well positioned to win the Liberal nomination and is the frontrunner heading into a federal by-election, a new poll suggests, even as his NDP opponent gains the endorsement of two former Liberal staffers.

The riding of Trinity-Spadina in downtown Toronto was vacated in March when Olivia Chow resigned to run for mayor. The vote to replace her will come by the end of the year, and may occur at the same time as four other federal by-elections split between Alberta and the Greater Toronto Area.

A new poll from Forum Research suggests Mr. Vaughan, who announced last week he was seeking the Liberal nomination, may have the advantage heading into the by-election. Eighty-four per cent of respondents said they knew who Mr. Vaughan was, compared to 58 per cent for Joe Cressy, a social activist who recently won the NDP nomination. Two of Mr. Vaughan's opponents for the Liberal banner, Christine Tabbert and Ryan Davey, had name recognition among only 10 and 9 per cent of respondents. Former Liberal candidate Christine Innes had 74 per cent name awareness.

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That familiarity appears to boost the Liberal party's prospects in Trinity-Spadina. When respondents were asked which candidate they would vote for in a series of head-to-head matchups – which included Conservative and Green candidates – a majority supported Mr. Vaughan over the NDP's Mr. Cressy, while the New Democrat had the most support when facing any other Liberal candidate.

Lorne Bozinoff, president of Forum Research, says the amount of swing in support due to Mr. Vaughan's name is very unusual.

"We know in by-elections that local issues are important," Mr. Bozinoff said. "...[Mr. Vaughan]'s a local councillor, well known, well liked. That makes a big difference."

Trinity-Spadina, which had been held by Ms. Chow since 2006, would likely have the NDP leading the poll if names weren't mentioned, he said. That may mean it could be up to the NDP's get-out-the-vote efforts to win the election, he said.

Forum conducted its interactive voice response telephone survey with 517 respondents on April 21. (Read how so-called robocall polling works.) The poll's numbers are considered accurate plus or minus 4 per cent, 19 times out of 20.

In the last set of federal by-elections in November, the electoral result was within Forum's margin of error in two ridings in Montreal and Toronto. Their numbers were significantly different from the actual vote in two ridings in Manitoba.

Mr. Vaughan will formally launch his campaign for the Liberal nomination at a local pub Wednesday night.

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The fight for the party's nomination heated up in recent weeks, when Ms. Innes, who had contested two elections for the party, was barred from running a third time. She is currently suing Liberal Leader Justin Trudeau and Ontario campaign co-chair David MacNaughton over their public claims about why she was dismissed.

Meanwhile, the NDP's Mr. Cressy announced endorsements Wednesday that included two former Liberal staffers.

Warren Kinsella, who worked in the campaign war rooms of former prime minister Jean Chretien and former Ontario premier Dalton McGuinty, said Mr. Cressy is a "great guy."

"He's the kind of guy who jumped out of the womb as a Member of Parliament," Mr. Kinsella said, adding that he would have supported him in the by-election no matter which party he was running for.

"He's quite moderate and sensible. I don't think there's a radical bone in his body."

Mr. Kinsella is currently involved in Ms. Chow's mayoral campaign.

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Lisa Kirbie, a former assistant to then-Liberal leader Michael Ignatieff and Mr. Kinsella's partner, also endorsed Mr. Cressy in the by-election, along with Mr. Ignatieff's brother Andrew.