Liberal Leader Michael Ignatieff insists his party is ready to "fight for the Canada we love" amid increased speculation that Canadians may soon be headed to the polls for a spring election.

Liberal Leader Michael Ignatieff says his party will not be the 'guarantors' of the future of the Conservative government. (Pawel Dwulit/Canadian Press)In a fiery campaign-style address to the Liberal caucus in Ottawa on Tuesday, Ignatieff insisted his party was not trying to provoke an election and added he did not know when the next one would occur.

But he said Liberals would not be the "guarantors of the future" of Prime Minister Stephen Harper's minority Conservative government.

"We are here to oppose and replace," he said.

Ignatieff mocked the latest round of Conservative ads, including a spot featuring Harper working late in his office.

The ads, Ignatieff said, offer a contrast between "leadership that listens and leadership that wants to impose an ideology Canadians just aren't comfortable with."

"You see this home alone guy, hasn't got any friends, doesn't get out much. I felt kind of sorry for him, really. … He's not listening to anybody."

The Prime Minister's Office quickly hit back after Ignatieff's speech, saying the Liberal leader was "once again" pushing for an "unnecessary and opportunistic election."

"Our government continues to be focused on the economy, including creating jobs and economic growth and keeping taxes low,” a spokeswoman wrote in an email to CBC News on Tuesday.

Pre-budget jockeying

The Tories have so far indicated they won't meet key opposition demands for the upcoming budget, including rolling back corporate tax cuts. They must secure the support of at least one opposition party to avoid a defeat of their government in a confidence vote in the House of Commons.

The Liberals have already said they will not support the budget unless the corporate tax rates are restored to 2010 levels, leaving the Bloc Québécois and New Democratic Party as possible suitors for the Conservatives.

In his rally speech, Ignatieff dismissed the Conservatives' claims that a Liberal government aims to increase the tax burden on Canadian families by rolling back the corporate tax rates — which the Tories are dubbing a "job creator tax."

“It’s not going to happen," he said. "Don’t believe what they tell you."

The Liberal leader said the question of election readiness isn't about organization, platforms or planes — although he noted those things sounded "pretty good" to him.

"There's another question, a deeper question: Are we ready to serve the people who put us here?" Ignatieff asked, then answered with shout: "The answer is yes, yes, yes."