TORONTO – Canada’s main opposition party vowed yesterday to try to topple Prime Minister Stephen Harper’s minority government at the first opportunity, which could force a fourth election in the last five years and the second in just a year.

Liberal opposition leader Michael Ignatieff’s announcement means the Conservative government could be toppled in a confidence vote if Canada’s two other opposition parties also vote to bring down the government.

‘Mr. Harper, your time is up. The Liberal party cannot support this government any further,’ Ignatieff said. ‘We will hold Stephen Harper to account, and we will oppose his government in Parliament.’

Harper now needs support from at least one of three opposition parties to stay in power. The Bloc Quebecois and New Democrats would have to do an about-face to back Harper.

The Liberals will have their first opportunity to present a motion of non-confidence in the first week of October. Liberal lawmaker Bob Rae later said the party would push for a vote at the first opportunity.

Ignatieff has been the party’s leader since December and doesn’t want to be seen as propping up the government, as former leader Stephane Dion did dozens of times before losing the election last October.