Stephen Harper has announced three federal byelections for late November to fill vacant seats in Parliament.
The prime minister set Nov. 29 as the date for votes in two Manitoba ridings and one in Ontario.
A Conservative source told The Canadian Press the Tories expect the Liberals to take at least two seats.
That puts the pressure on Michael Ignatieff's Liberals as strong Tory and NDP candidates emerge.
Former Ontario Provincial Police commissioner Julian Fantino will be running for the Tories in Vaughan after receiving the Prime Minister's public backing last week. Already a well-known name, Mr. Fantino will be running against NDP candidate Kevin Bordian and Liberal Tony Genco, who will be confirmed as a candidate this weekend.
Mr. Genco is supposed to be a familiar face on the local level, sitting on the library and hospital boards in the area. He is also a founding board member of the Vaughan Social Action Council.
Vaughan was held by Liberal Maurizio Bevilacqua for the past 22 years. Mr. Bevilacqua is now running for mayor of Vaughan.
Some analysts have predicted the loss of Vaughan would be disastrous for Liberal Leader Ignatieff, akin to the party's devastating defeat in Montreal's Outremont riding in a 2007 by-election.
The loss of Outremont, a longtime Liberal stronghold, sparked an internal revolt against then-leader Stéphane Dion.
Mr. Ignatieff tried to play down the importance of the Vaughan by-election.
"I wouldn't overdo Vaughan," Mr. Ignatieff told reporters Friday, anticipating the by-election call. "I think it's important. It's a seat where we've been proud to have had Liberal support for a long time. ... Let's not overdo it, let's not underdo it. Let's let the voters of Vaughan decide."
Mr. Ignatieff said he intends to campaign personally in the by-elections.
The Manitoba by-elections will take place in Winnipeg north and Dauphin-Swan River-Marquette, which both fell vacant when MPs chose to run for political posts at the municipal level.
Robert Sopuck will be running for the Conservatives in Dauphin-Swan River-Marquette, while a Liberal candidate has yet to be determined. The riding was previously held for years by Tory Inky Mark, who is now campaigning in Dauphin's municipal election.
Mr. Sopuck, an environmentalist, biologist, farmer and writer, is considered a favourite for the seat given his reputation as an outspoken advocate for Manitoba's rural communities.
He was recently a natural-resources consultant, supervising an oil-exploration program in Alberta last winter, and has advised the federal government on environmental and natural-resources policy. He is also the hunting and outdoors columnist for the Winnipeg Free Press newspaper.
Meanwhile, the Winnipeg North riding fell vacant last April when former NDP MP Judy Wasylycia-Leis chose to run for mayor. NDP candidate Kevin Chief is running for the seat against Liberal MLA Kevin Lamoreux and Tory Julie Javier.
The NDP has held the riding since 1997 and NDP national director Brad Lavigne says the party is going to work hard to keep the seat.
"It's going to be a very tough race," he said. "We take nothing for granted."