Canada's three opposition parties have said they plan to topple the conservative government in a vote of no confidence in Parliament and trigger the country's fourth election in seven years.
Prime minister Stephen Harper needs the support of at least one opposition party to stay in power, but all three rejected Mr Harper's proposed budget after it was announced on Tuesday.
The trigger that is expected to bring Mr Harper down are allegations - supported on Monday by a Parliamentary committee - that Mr Harper has acted in contempt of Parliament by failing to disclose the full financial details of his tougher crime legislation, corporate tax cuts and plans to purchase stealth fighter jets.
The opposition is set to introduce a no-confidence vote on the contempt issue tomorrow, which could trigger an election that would take place either May 2 or May 9.
"This government has lost the confidence of Canadians," Liberal leader Michael Ignatieff said.
Earlier, Mr Harper urged the opposition to support his latest budget plan. And he called on opposition members to explain their refusal to support it during a time of economic uncertainty.
"Our economy is not a political game. The global recovery is still fragile. Relative to other nations, Canada's economic recovery has been strong, but its continuation is by no means assured," Mr Harper said.
Canada is likely to emerge from an election with little changed unless the opposition parties join forces in a coalition.
Opinion polls expect Mr Harper's Conservative Party to win, but not outright, meaning he will continue to govern with a minority in Parliament, dependent on opposition votes to stay afloat.
Mr Harper's Conservatives hold 143 seats in Parliament. The Liberals have 77, the New Democrats 36 and the Bloc Quebecois 47.