OTTAWA - As Prime Minister Stephen Harper helped ring in Quebec City's 400th birthday Thursday, a series of opinion surveys suggested his party has lost key support in the province.

The latest Canadian Press Harris-Decima poll finds that a bruising session in Parliament - along with a perceived values gap on the environment - has cost the Tories crucial ground with Quebec voters and urban women.

"The ability of the Conservatives to articulate a values-based agenda that really appeals to these folks hasn't been so successful," says Harris-Decima president Bruce Anderson.

Based on ongoing surveys, Anderson said these integral swing voters have tended to be at odds with the government for its push to extend the combat mission in Afghanistan, and its opposition to gay marriage.

"More prominently than anything else, though, has been the debate about the environment," Anderson says.

There is an especially strong urge among women and Quebecers for more action on climate change, he said.

"And their view of the Conservatives has been that (they) don't share the same passion for that issue or the same determination to make aggressive progress."

That said, the three-week average results of a weekly telephone poll of just over 1,000 people indicate the Tories and Liberals are tied at about 31 per cent of national support.

The NDP follows with 16 per cent, the Green party is at 12 per cent and the Bloc Quebecois is at nine per cent.

In Quebec, the three-week average result suggests 37 per cent support for the Bloc, 25 per cent for the Liberals, 17 for the Tories, 11 for the NDP and nine per cent for the Green Party.

The Liberals lead in Ontario at 38 per cent, with the Conservatives at 32, the NDP at 16 and the Greens at 13.

Support for the Tories has also dipped in Ontario outside the greater Toronto area, especially in the eastern 613 area code, Anderson says.

"I think it's been tougher for the Conservatives to continue to occupy the advantage they created in 2006."

The Liberal brand has begun to recover as the sponsorship scandal dissipates and leader Stephane Dion proposes a bold and high-risk carbon-tax strategy.

The Tory government, meanwhile, spent the spring fending off a barrage of its own bad press - from the Mulroney-Schreiber probe to the security breach that forced Maxime Bernier to resign as foreign affairs minister.

"Being in Ottawa, being in the House of Commons, has been unhelpful for the Conservatives more recently," said the pollster.

"And typically what happens when the House rises is their support levels bump a little bit."

That may well happen again, says Anderson, who adds it had better if the Tories are to triumph in a federal campaign that could be triggered as early as this fall.

"I think they would be challenged to repeat their success of 2006 with the kind of numbers we've seen in the last month or two - let alone do better than that."

The poll suggests the Liberal advantage among women living in cities has increased to 10 percentage points over the Tories from five since December.

In Quebec, results indicate the Tories lost a 15-point lead with voters who say they're neither federalist nor separatist - and are now tied with the Liberals.

The most recent weekly poll was conducted June 26-29 and is considered accurate to within 3.1 percentage points 19 times in 20. Regional breakdowns have higher margins of error, which is why Harris-Decima uses three-week rolling averages to increase the sample size.