While Stephen Harper danced around a challenge to go toe-to-toe in a debate with his Liberal rival Thursday, Michael Ignatieff reiterated his willingness -- both online and in the flesh -- to take part.

On Twitter, the Liberal leader again laid down the gauntlet, writing: "The consortium debates are set. How about that one-on-one, Mr. Harper?"

Ignatieff also fired a salvo at Harper during a campaign stop in Winnipeg, a day after he accepted what appeared to be a suggestion from Harper for a one-on-one battle of wits.

"If he's walking away, that kinds of tells you what you want to know about whether you can trust this man," said Ignatieff in the Manitoba capital.

But as the proposal gained steam online and became a hot topic Thursday on Twitter and other social networks, the likelihood that Canadians will see an exclusive showdown between the two major party leaders seemed less likely as the day wore on.

In Halifax, Harper -- who first brought up the debate idea during a press conference on Wednesday -- used a question about the proposal to instead label his opponent as bent on creating a coalition with the NDP and the Bloc Quebecois.

Harper also appeared to back away from the tete-a-tete battle with Ignatieff, who is a former Harvard professor and public academic who once hosted a TV show on the BBC.

"Our first preference was to have a debate with the leader of the coalition," said Harper. "Mr. Ignatieff insisted his first preference was to have his coalition partners at the debate."

Harper also deferred to the decision of the broadcast consortium, who has said that only the four major party leaders will be allowed to take part in the television debate.

"We're not interested in multiple debates," Harper said.

In response to Harper's apparent demurring, Ignatieff said "24 hours ago, he was swaggering. And now we are we are."

Meanwhile, NDP Leader Jack Layton also threw his hat into the ring and offered to take on Harper in an individual debate.

But nearly lost in the torrent of challenges and counter-challenges, however, was the voice of the Green Party's Elizabeth May, who had complained earlier this week about being shut out of the debates.

While May managed to get into the 2008 debates thanks to an agreement from the other party leaders, she remains shut out this time around by the consortium of broadcasters, of which CTV is a member.

May began a push for a judicial review of the situation, and the Greens have hired a lawyer to argue their case. The consortium has maintained that only parties with seats in Parliament can take part.

The English debate is set for April 12 while the French debate will occur two days later.

While those broadcasts will likely feature the quartet of Harper, Ignatieff, Layton and Bloc Quebecois Gilles Duceppe, viewers girding for the two-man battle will likely be appeased by planned one-on-one segments.

With a report from CTV's Roger Smith and The Canadian Press