Both Elizabeth May and Stéphane Dion categorically dismissed reports of any collusion after two Green candidates threw their support behind the Liberals days ahead of the Oct. 14 vote.

Danielle Moreau withdrew from the race in Longueuil-Pierre-Boucher on Thursday to help secure a victory for rival Liberal Ryan Hillier, saying she had no chance of winning and hoped to keep Conservative Leader Stephen Harper out of power.

On the same day, in Montmagny-L'Islet-Kamouraska-Riviére-du-Loup, Green candidate Claude Gaumond told Radio-Canada, CBC's French-language network, that voters should support the Liberals.

May posted comments on the Green website denying media reports she was urging strategic voting across the country as "complete nonsense."

"As I have said over and over, strategic voting is generally not a sound strategy at all and I do not support it," May said.

"I am not making deals with other parties, and the Greens are not in discussions with other parties."

Speaking on CBC Newsworld Friday, Dion also rejected any suggestion of a strategic deal between the two environmentally minded parties.

The Liberals have made an agreement with the Greens not to run a candidate in Central Nova, where May is seeking to unseat with Conservative incumbent Peter MacKay. In return, the Greens aren't running anyone in Dion's St. Laurent-Cartierville riding.

"Everything we do is in the public," Dion said. "We have this agreement because we put the interests of Canadians before narrow politics, narrow partisan politics."

May has said she wants the Liberal leader to become the next prime minister, but stressed she wants Canadians to elect Green members of Parliament to the House of Commons.

But Dion sought again to lure voters from other parties, warning: "The only way to stop Harper is to vote Liberal now."

"Canadians never will you have a greener prime minister than me," he said.

The Greens saw a rise in support in the early days of the five-week election campaign, but saw it plateau around 12 per cent less than two weeks, according to a rolling opinion poll by Canadian Press/Harris-Decima.