Harper blasted the opposition in a televised address. "They want to take power, not earn it," said Harper, whose Conservatives won enough votes in the Oct. 14 election to stay in power.
The opposition Liberals, New Democrats and Bloc Quebecois are discussing the option of a new government despite last month's vote, said Karl Belanger, a spokesman for NDP leader Jack Layton.
The Liberals said they are considering introducing a motion declaring no confidence in the minority Conservative government but no decision has been made. A defeat on such a vote by Harper's party could set the stage for another election or give the opposition a chance to form a government.
No federal government has ever been ousted in favor of an opposition coalition.
Though Harper's party retained power last month, it did not win the majority of parliament's 308 seats and must rely on opposition support to pass budgets and legislation.
Opposition members in parliament said they cannot support the government's updated fiscal plan, introduced by Finance Minister Jim Flaherty on Thursday, because it offers no stimulus package to deal with the global meltdown.
The opposition said it was considering introducing a motion on Monday, but Harper said he was delaying all votes that could topple his government until Dec. 8.
Harper defended his response to the economic crisis, saying he had acted to keep taxes low and that in the next couple of months his party will introduce a budget that will includes a stimulus package.
He said the opposition's only concern is taking over the government.