Mr Harper has said Conservatives must win a majority in parliament to avoid being challenged by a coalition Polls in Canada have opened for the fourth federal general election in seven years.
Prime Minister Stephen Harper has warned if his Conservatives do not win a majority in parliament, he could be toppled by a leftist coalition.
Recent opinion polls suggest the New Democratic Party (NDP) has made large gains in the past several weeks.
Mr Harper’s minority government was forced into an election after a non-confidence vote in parliament.
The vote came after Mr Harper’s government was found to be in contempt of parliament because of its failure to disclose the full costs of anti-crime programmes, corporate tax cuts and plans to purchase stealth fighter jets from the US.
Mr Harper, who took power in 2006, has seen his advantage in the election dwindle during the past several weeks, with the left-leaning NDP experiencing an unexpected surge in popularity.
The prime minister made a final appeal on Sunday for a “strong, stable, Conservative majority government”, warning the NDP and Liberals could form a coalition blocking economic policies his party wishes to push forward.
Figures released on Sunday by private polling firm Ekos indicated 34% support for the Conservatives, with the NDP, which ran a distant third at the beginning of the campaign, at 31%.
Pollsters at Ekos, who said they questioned 2,876 Canadians in the survey, reported the Liberal Party was trailing at 21%.
Experts suggest a narrow Conservative lead would make it unlikely the party would win a majority of the seats in the House of Commons.
But there is a possibility the left-centre vote could be split between the NDP and Liberals, allowing Mr Harper to squeeze out a majority.
Mr Harper has won two elections but never with a majority in parliament’s 308 seats.
“We can change the government. We’re not just going to oppose Mr Harper, we’re going to replace him,” said NDP leader Jack Layton.
Mr Harper, a 52-year-old career politician, has said a win by the NDP could lead to out-of-control spending and higher taxes.
Mr Layton, who favours high taxes and more social spending, has been a critic of Alberta’s oil sands sector, the world’s second largest oil reserves.
Mr Harper has also said the Liberal Party, the largest opposition party, led by Michael Ignatieff, cannot be trusted to handle the economy.
Mr Ignatieff, a 63-year-old former Harvard University professor, has accused Mr Harper of deceit, and has also said that Canadians have no confidence in his ability to look after the nation’s finances.
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