OTTAWA — A third-party surge has unsettled the status quo as Canada prepares to go to the polls on Monday, with Conservative Prime Minister Stephen Harper seeking an ever-elusive majority government.

The run-up to Canada's fourth election in seven years has been dominated by speculation over how the surging support in opinion polls for the left-leaning New Democratic Party (NDP) will play out.

Harper and the Tories failed to earn an overall majority in both the 2006 and 2008 elections, leaving themselves prey to opposition parties bringing the government down, as on this occasion, with a vote of no confidence.

The Conservatives lead all three main opposition parties in pre-election surveys but remain shy of the support needed to win a majority of seats in parliament.

"The most reasonable assumption at the moment is that the Conservatives will win another minority government," Jon Pammett, a politics professor at Carleton University in Ottawa, told AFP.

"But it's not clear how long another Harper (minority) government will last because he seems to have ruled out working with the other parties."

Harper himself has warned that a second-place NDP could form a coalition with the Liberals to seize power if the Conservatives fail to win a majority of the 308 seats in parliament.

But analysts are skeptical that the NDP's stunning rise in the polls will translate into a projected tripling of seats from 36 prior to the dissolution of parliament, to leapfrog the Liberals and the separatist Bloc Quebecois.

There are even suggestions that vote-splitting on the left could help the Conservatives win more seats in key battlegrounds such as Ontario province.

"It's far too soon to be talking about a cataclysmic shift to the left," Pammett said.

Harper, the first prime minister of the newly reformed Conservatives after the 2003 merger between the Progressive Conservative Party and the Canadian Alliance, had seemed more set for a landmark majority earlier in the campaign.

He touted his government's strong fiscal record and a "stay the course" plan to firm Canada's economic recovery, while the centrist Liberals, which ruled for most of the last century, tracked left to counter him.

Then in the final week of the campaign the NDP emerged from the shadows to post a strong challenge to the Liberals for the role of official opposition, calling for an end to oil firm subsidies and a hike in corporate taxes.

NDP leader Jack Layton currently enjoys an 8.5 percent lead over Harper in terms of personal popularity -- 33 percent, to Harper's 24.5 percent, according to a recent poll.

Layton has proposed a massive boost in social spending, although critics view his arithmetic as unrealistic.

"Overall, it's not been the kind of campaign that captures the public's imagination," said Pammett.

"The prevailing sense is that we're in a time of austerity," he explained, "after rolling out a major stimulus package to try to get out of the 2008 economic downturn and the debt accumulated as a result of that.

"You can tinker around the margins and give little breaks here and there, but it's very difficult to conceive of expansive and expensive new government programs."

As such, party platforms have not resonated with voters, who also do not appear to have been swayed by dire warnings of economic or constitutional chaos if the Conservatives are again denied a majority.

Pollsters pointed to the party leaders as one of the main drivers of voting intentions.

Layton, who has come under increasing attack from other party leaders in recent days, is viewed as the most trustworthy. But Harper is still seen as the most competent to lead the nation.

Liberal leader Michael Ignatieff, the only new party head in this election, has struggled to connect with common people since his arrival on the political scene in 2006 after three decades spent abroad.

Still optimistic, on Thursday he told reporters: "People don't get elected by polls, they get elected by voters... and many voters have not actually made their choice yet."