The federal Liberals have leaped from third to first place in voter support in Atlantic Canada, a new poll shows, with a high-ranking Grit citing Justin Trudeau's leadership campaign as the key ingredient.

Halifax-based Corporate Research Associates reported Tuesday that 36 per cent of voters would back the Liberals if a federal election were held now.

That's up from 23 per cent a year ago, said CRA, which does such a poll every three months, and it marks the first time the once-dominant Liberals led the polls since the summer of 2010.

CRA found that the Conservatives and NDP were tied at 30 per cent each of support among decided voters.

New Brunswick MP Dominic LeBlanc said the rise in support can be attributed to Montreal MP Justin Trudeau, who formally launched his bid for the Liberal leadership in October, as well as Conservative policies.

CRA interviewed 1,500 adults in the four Atlantic provinces between Nov. 7 and Dec. 1. The poll has a margin of error of 2.5 per cent, 19 times out of 20.

The poll found that the Liberals have made gains largely at the expense of the Conservatives, who lost nine percentage points over the last 12 months. The NDP dropped from 36 per cent to 30 per cent over the same period.

Prime Minister Stephen Harper remains the top choice among the three political leaders, with 28 per cent support from voters. Interim Liberal Leader Bob Rae ranked second at 24 per cent. NDP Leader Tom Mulcair trailed at 22 per cent, with Green Leader Elizabeth May at seven per cent.