The poll, which comes more than two years before the next federal election, has the Liberals in first place at 35.4 per cent. The Conservatives are 4.1 percentage points back, at 31.3 per cent and the NDP are at 23.6 per cent.
The numbers are considered accurate to within 3.3 percentage points, 19 times out of 20.
That puts the Liberals up several percentage points from the last poll two months ago, when they sat in second place at 29.1 per cent. The Conservatives were ahead in that poll with 31.5 per cent and the NDP in third at 27.2 per cent.
The number of people polled who said they were undecided has plunged since the last survey, from 28.3 per cent last February to 11.2 per cent this month.
The Liberal Party has had substantial media coverage in the past few months as they ramp up to reveal their next leader this weekend.
"It is too early to tell whether this increase in Liberal support is the new trend or a direct result of the focus on the Liberal Leadership race," Nik Nanos, the president and CEO of Nanos Research, told CBC News.
"What is clear is that the focus on the Liberal leadership is having reverberations on the political landscape," he said.
The last three times the Nanos poll suggested the party had surpassed the Conservatives were:
- In early 2006, just after Stéphane Dion won the party's leadership.
- In fall 2008, just before that year's federal election.
- In spring 2009, when Michael Ignatieff won the party's leadership.
Nanos Research recruited 1,002 Canadians, 18 years of age or older, by phone and then administered an online survey. The survey was conducted April 4 to 8, 2013.
People polled were asked: "For those parties you would consider voting for federally, could you please rank your top two current local preferences?"
The February poll was considered accurate to within 3.7 percentage points, 19 times out of 20.
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