OTTAWA - The country's two leading political parties are finding that pipeline politics is having a significant effect on voter's partisan preferences, a new poll says.

The federal Conservatives, strong proponents of the proposed Northern Gateway pipeline which would carry Alberta crude over the Rockies to the northern B.C. port of Kitimat, have seen their support slip three percentage points since June to 35% in the province, Abacus Data found in a new poll provided exclusively to QMI Agency.

Meanwhile, 40% of British Columbians would vote for the federal New Democrats who, like their provincial cousins, oppose the pipeline.

Abacus paid special attention to B.C. for its latest poll in the belief that province's political volatility over the next few years make a big difference in the next federal election.

"I think that's going to be the battleground in 2015," said Abacus Data CEO Coletto. "The NDP has set their sights on this province."

B.C. will be even more important in 2015 because the province is getting six more seats in the House of Commons, boosting its total to 42.

Abacus "over-sampled" its B.C. component for the poll, asking 793 there for their vote intentions.

On a national basis, Abacus surveyed 2,099 between Aug. 10-12 and found the Conservatives at 37% compared to the New Democrats at 32%. Most polls since late spring have shown Stephen Harper's Conservatives trailing or tied with Thomas Mulcair's New Democrats.

The Liberals and the Greens remain unchanged from the beginning of the summer with 20% and 6% support respectively.

In Quebec, the NDP are about as popular as they are in B.C. with 41% support, while the Bloc Quebecois come in second at 25%.

Abacus drew the survey participants from an online panel of more than 150,000 Canadians.

Abacus said it weighted the data for age, gender and other factors to mirror the latest Canadian census data. The pollster did not provide a margin of error for its results because panellists were not selected randomly. The margin of error for a randomly-selected panel of 2,099 is plus or minus 2.2%, 19 times out of 20.