OTTAWA (Reuters) - Canada’s once-popular opposition Liberals, who are trailing in third place ahead of an Oct 19 election, shifted their fire to the first-place New Democratic Party on Wednesday as the two center-left rivals battle to defeat the ruling Conservatives.

Canada's Liberal leader Justin Trudeau speaks during the Maclean's National Leaders debate in Toronto, August 6, 2015. REUTERS/Mark Blinch

Liberal leader Justin Trudeau said the NDP, which has a narrow lead in recent opinion polls, was misleading voters with promises to increase spending while balancing the budget.

The Liberals and NDP are both battling to win over center-left voters to defeat Prime Minister Stephen Harper, whose Conservatives are seeking a rare fourth consecutive term after nine years in power.

Vote-splitting between the Liberals and NDP helped the Conservatives win the last election, in 2011.

Battling a perception that his party plans big spending increases, NDP Leader Thomas Mulcair says it will balance its first budget.

Trudeau said the NDP’s promise would hurt the economy.

“Mr. Mulcair is being entirely disingenuous,” he told a news conference in Newmarket, Ontario. “In the midst of a recession, Canada doesn’t need billions of dollars worth of cuts to the economy. That hurts Canadians, and it’s poor economic policy.”

Trudeau favors investments in infrastructure to help bolster the economy and says a Liberal government would not rush to balance the budget after what he said was the mess that Harper had made of the economy.

The Conservatives, who have run seven consecutive budget deficits, are promising a surplus in the 2015/16 fiscal year.

An Angus Reid online poll released on Wednesday put the NDP in first place, with 36 percent support among likely voters. The Conservatives are second with 32 percent, while the once high-flying Liberals got just 23 percent support.

The survey suggests the NDP would win a weak minority government, leaving it to rely on support from the Liberals to pass key legislation. Trudeau has ruled out the idea of a formal coalition.

Mulcair brushed off Trudeau’s attack, telling reporters in London, Ontario that he would raise taxes on large corporations and cut some personal tax breaks to help fund his proposals.

Mulcair said that as he listened to the Conservatives and Liberals both attacking his plans, “I am driven to the conclusion that we’ve got the most balanced approach.”

The three parties have yet to release detailed policy platforms.