TORONTO - Canada's opposition Liberal Party elected Michael Ignatieff its leader yesterday, and the former Harvard University professor warned he would try to oust Prime Minister Stephen Harper's minority Conservative government if it failed to address the economic crisis.

Ignatieff, 61, could become Canada's next prime minister if the Liberals and two other opposition parties stick with a plan to vote out Harper next month and are allowed by the governor-general to form a coalition government.

Ignatieff said it would all depend on what is in next month's federal budget, suggesting the Liberals would be appeased by a significant economic-stimulus package.

"I'm prepared to vote no-confidence in this government if the government does not present a budget in the national interest," he said.

Stephane Dion left as Liberal leader after Harper last week temporarily foiled an effort to topple him.