A vitriolic first day of campaigning kicked off Saturday with Conservative Leader Stephen Harper accusing his political opponents of vying to form a coalition government after the election.

Gov. Gen. David Johnston dissolved Parliament Saturday morning at the prime minister's behest, paving the way for a vote that Harper announced would take place May 2.

The election was triggered after MPs voted Friday in favour of a Liberal motion that said Parliament had lost confidence in the government. The motion cited a ruling earlier in the week that found the Conservatives in contempt of Parliament.

After visiting the governor general, Harper charged that the Opposition had forced an election that threatens the country's economic recovery, and claimed that the Liberals would form a coalition with the two other opposition parties if another minority government is elected.

"Canadians need to understand clearly, without any ambiguity: unless Canadians elect a stable, national majority, Mr. Ignatieff will form a coalition with the NDP and Bloc Quebecois. They tried it before. It is clear they will try it again. And, next time, if given the chance, they will do it in a way that no one will be able to stop," Harper said.

The Conservatives have placed the idea of a coalition government front and centre in recent weeks, hoping to make it a major election issue.

Liberal Leader Michael Ignatieff had refused to come out and clearly say that he wouldn't form a coalition. But on Saturday, he issued a statement that ruled out "coalition with other federalist parties," even though coalitions are a legitimate constitutional option.

The wording was tougher when it mentioned the Bloc Quebecois.

"We categorically rule out a coalition or formal arrangement with the Bloc Quebecois," the statement said.

Bloc Quebecois Leader Gilles Duceppe took direct aim at the Conservatives in his campaign kick-off speech Saturday morning, warning about the consequences of handing Harper a majority government.

"The leader of the Conservatives wants to obtain a majority to impose his ideology without any limits. To get there the Conservatives won't hesitate to repeatedly assault the very principles of democracy," Duceppe said.

He also claimed that Harper had lied to Canadians about governing with other opposition parties. In 2004, he said, Harper was open to the idea of forming a pact in Parliament with the other opposition parties.

"Harper lied to the people, he agreed with the coalition," Duceppe wrote on Twitter later in the day, in French.

The Bloc Quebecois also posted to its website a 2004 letter to the governor general signed by Harper, Duceppe and NDP leader Jack Layton that said the three opposition parties "constitute a majority in the House, and have been in close consultation."

Should Paul Martin's minority Liberal government fall on a non-confidence motion, it said the governor general should "consult the opposition leaders" and consider all options, implying that the opposition parties could take the reins.

The letter did not contain the word "coalition," and Harper said at the time the letter did not signify an intent to form a coalition.

But Duceppe wrote that he remembered a meeting in 2004 in which Harper "definitely talked about a coalition."

On the campaign trail

At a rally in Edmonton, Layton had few words for Ignatieff but spent much of his speech attacking Harper over ethical controversies.

When Harper was first elected as leader of the Conservatives he pledged to "end Liberal-style scandals," Layton told the crowd.

"Instead, he's just simply replaced them with his own scandals," he said to applause.

"Didn't he say he would clean up Ottawa patronage? Well he appointed more friends, and insiders and even campaign fundraisers to cushy public finance jobs in the Senate than any Liberal prime minister ever did."

Ignatieff spent most of the day campaigning in Ottawa before heading to a rally in Montreal. He painted the Liberals as a party that cares about Canadian families, and an alternative to what he called the Conservative lack of ethics, and misplaced economic priorities.

"This election is about choosing the kind of Canada we want to be. A Conservative vote means $6 billion for more tax breaks for the largest corporations, $13 billion to build U.S.-style mega-prisons, and $30 billion to buy stealth fighter jets -- all of it with borrowed money on Harper's record deficit," Ignatieff said.

Meanwhile Harper played down opposition charges that his government is tainted by scandal, after it was found in contempt of Parliament.

"The Canadian public doesn't care about the maneuvers of Parliament," Harper said.

Later in the day, Harper travelled to Quebec City to reach out to voters in the province, where his party hopes to build on the 11 ridings it won in the last election.

To that end, the Conservatives have dedicated a separate campaign bus for the province, to be headed by Harper's Quebec lieutenant, Christian Paradis.

"I start my speeches in French and I remind people of this because Canada as a great continental nation was first conceived in French right here in Quebec, right here in Quebec City," Harper told supporters.

"The citizens of the Quebec City region want to be in the centre of the action, it's here that the country was founded in French, a little more than 400 years ago," Harper told a crowd of supporters at a Quebec City community centre.

While Layton, Ignatieff and Harper kicked off their campaigns in or near Ottawa on Saturday, Green Party Leader Elizabeth May launched her bid for a seat in Parliament on Vancouver Island.

May, looking to become the Green Party's first elected MP, is running against Conservative Gary Lunn in the riding of Saanich-Gulf Islands.

May promised that, should she be elected, she will work to bring greater civility to the House of Commons.

Government falls

On Friday, a few moments after the non-confidence vote was passed in the House of Commons, Parliament was adjourned and papers went flying into the air before MPs vacated their seats, many of them for the last time.

The party leaders quickly got into election mode, outlining their key positions and setting up their campaigns for the official election call expected Saturday morning.

Early this week, all three opposition party leaders signalled their intention to reject the federal budget introduced by Jim Flaherty on Tuesday.

Though the document is now effectively obsolete -- it would have been voted on by MPs next week if the government had survived -- it is expected to form the basis of the Conservatives' election campaign.

Canadians will have roughly five weeks to sort through the spin, and choose the country's future government.

With files from The Canadian Press