OTTAWA - A polarized electorate may be tilting toward the federal Liberals at the expense of Stephen Harper's Conservative government, a new poll suggested Monday.

The Canadian Press Harris-Decima survey compared attitudes toward the Tories and Liberals in a head-to-head, two-party format. The telephone poll of just over 1,000 Canadians found that 44 per cent of respondents said they'd prefer a Liberal government after the next election, compared with 37 per cent who preferred the Conservatives.

The trend held true in every region except the three Prairie provinces, where more respondents favoured a Tory outcome.

Harris-Decima's weekly voting intention numbers had the Conservatives at 32 per cent nationally, the Liberals at 31, with New Democrats at 15, the Greens at 12 and the Bloc Quebecois at six per cent.

Since the 2006 election, the Conservatives "have not been able to enlarge their tent," said Harris-Decima president Bruce Anderson - notwithstanding a generally strong economy, fat government coffers and the incumbent's opportunity to control the agenda.

"If anything, the leaning and the second-choice support profile of Canadians is disproportionately headed in the direction of the Liberals right now," said Anderson.

He said the poll, conducted Thursday through Sunday, was premised on the idea of a sharply polarized election campaign in which the ballot question becomes a stark choice between the incumbent Tories and the only practical alternative.

"There's more opportunity underneath the surface for the Liberals than there has been perhaps at any time since the last election - and therefore more risk for the Conservatives if they can't find new and better ways to enlarge the tent of potential supporters."

NDP supporters told Harris-Decima they'd prefer a Liberal government by an almost four-to-one margin (69-18) compared with the Tory alternative, and Green supporters favoured the Liberals more than two to one (58-28).

Only Bloc Quebecois supporters were more favourable to a Conservative outcome, by a 41-32 margin.

The survey, which has a margin of error of plus or minus 3.1 percentage points, 19 times in 20, indicates Prime Minister Stephen Harper beats Liberal Stephane Dion on leadership attributes (35-26). The Tories trail the Grits on questions of front-bench strength (26-20), values (35-29), and ideas for the future (31-28).

Tory leadership is "the strongest card in their hand," said Anderson, but when it comes to tapping into the public mood on policy and values, they appear to be wanting.

"They probably need to do more than just say what's wrong with the Liberal plan."

The survey was released as the Tories released a new ad campaign attacking Dion's carbon-tax proposal, while simultaneously staring down the Liberals on a final major confidence vote in the Commons before Parliament's summer recess.

Liberals abstained in large enough numbers Monday evening to permit the Tory budget implementation bill - including controversial changes to the Immigration Act - to pass third and final reading.

The Liberals are not bucking the public mood in this respect.

The poll found that just eight per cent of respondents want an election this summer, 27 per cent would prefer a fall vote and 52 per cent prefer an election further down the road.

Neither the Liberals nor Tories have made a case why we need to go to the polls now, said Anderson.

"People are not seeing a crisis of governance right now so they don't see any imminent need or benefit that would be served by having an election."