Popular Quebec MP Maxime Bernier is expected to be the first to formally register for the contest and Ontario's Kellie Leitch may not be far behind.
Maxime Bernier is shown on the campaign trail in the riding of Laval-Les Iles, in Laval, Que., September 22, 2015. (Photo: Mario Beauregard/CP)
Both have made no secret of their leadership ambitions in recent months, with Bernier setting up a website and printing T-shirts ahead of a conservative conference in February.
Leitch has been criss-crossing the country, collecting signatures, volunteers and money to help back her bid.
Others contemplating a run include MPs Andrew Scheer, Jason Kenney, Lisa Raitt, Tony Clement and Michael Chong.
Many have their eye on next month's party convention and are weighing the odds of formally registering to run now or waiting to gauge support there.
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