A Liberal-NDP coalition agreement that would replace the minority Conservative government was being fleshed out Sunday night, the CBC has learned.

Liberal Leader Stéphane Dion has shown the outline of an agreement between his party and the New Democratic Party to Liberal leadership candidates Michael Ignatieff, Dominic LeBlanc and Bob Rae, the CBC's Keith Boag reported, citing sources.

"They're discussing this tonight in Toronto," he said from Ottawa.

The NDP would hold 25 per cent of cabinet positions, Boag said, adding that the finance minister and the deputy prime minister would be Liberals.

The Bloc Québécois would not officially be a part of the coalition, but the new government's survival would depend on their support, he said.

The Harper government could prorogue Parliament to block the coalition efforts, but "that'd be a very, very dramatic step given the government has taken the position there'll be a budget early in January," Boag said.

"The real obstacle to this deal going through is still within the Liberal party," Boag said, adding the deal is being negotiated by Dion, who believes he has the right to be prime minister.

But it's unclear whether the party wants him to continue, and the leadership candidates were meeting Sunday evening to discuss the matter, Boag said.  

Opposition parties say they have lost confidence in the government of Prime Minister Stephen Harper after Thursday's economic update by Finance Minister Jim Flaherty failed to provide a stimulus package for Canadians.

Since then, the Liberals have been in negotiations to form a coalition with the NDP, and the concessions made by the Conservatives over the weekend have done nothing to change the parties' view that Harper must go.

On Sunday, Flaherty said the government would deliver the budget on Jan. 27, about a month before one is normally tabled in the House of Commons.

Shortly after his announcement, Transport Minister John Baird said the minority government won't try to eliminate the right to strike for federal civil servants over the next couple of years, as pledged in last week's economic update.

On Saturday, Baird also announced the government had shelved its contentious plan to eliminate political party subsidies that are based on the number of votes received during elections.

Parliament is due to vote on a Liberal no-confidence motion on Dec. 8. If the Conservatives lose, the opposition parties could be invited by the Gov. Gen. Michaëlle Jean to form a government.

Harper has been in office since February 2006.