The Conservatives' substantial lead over the Liberals appears to be narrowing, according to an opinion poll released as the second week of the federal election campaign got underway Monday.

The Canadian Press Harris-Decima poll, in partnership with the CBC, gave the Conservatives 38 per cent support across Canada, down from 41 per cent on Friday. They were followed by the Liberals at 27 per cent, up from 24 per cent on Friday.

 "If a federal election were being held tomorrow, who would you be voting for?"
 Conservatives 38%
 Liberals  27%
 NDP 16%
 Green party  9%
 Bloc Québécois  8%
  At least 1,343 Canadian adults interviewed Sept 11-14

Meanwhile, the NDP increased its national support by one percentage point to 16 per cent.

The Greens remained at nine per cent national support, while eight per cent of respondents said they favoured the Bloc Québécois.

"We have now ... a bit of a sign that say, a week ago, the Conservatives might have been flirting with that majority number we were talking about, but now, perhaps, not so much the case," said the CBC's David Taylor, who is tracking the polls.

Tories to be 'scrutinized': survey head

Harris-Decima president Bruce Anderson said the numbers suggested the lead Stephen Harper's Conservatives gained in the first week of campaigning, which featured advertising emphasizing Harper as a sensible, centrist choice, appears to be softening.

"The Conservatives set the tone and the pace they wanted in the week before and the week after the writ was dropped," Anderson said in a release.

But, he said, the campaign is now entering a different phase, in which voters will be looking more closely for signs that the Tories would govern from the centre instead from a more aggressively partisan or ideological position.

"The formula for the success the Conservatives employed in the last two weeks will be scrutinized more heavily by voters in the coming two weeks," he said.

'A gap has opened up': Liberal strategist

Party strategists weighed in on the poll Monday evening, with both Liberal and Conservative campaigns urging caution when interpreting the results of such rolling polls.

Conservative strategist Jaime Watt dismissed the polls as "public fetish."

"How they're being interpreted is not how we would use them as strategists," he told the CBC's Don Newman. "They're going to go up and they're going to go down.

"I think the interesting thing about the campaign is that it's begun to shake itself out in a particular way and I don't think you're going to see a lot of movement from that as the campaign goes forward."

The Liberal campaign agreed that such polls must be used with caution, but touted Monday's numbers as "good news."

"A gap has opened up," said Liberal strategist Scott Reid. "I'm very confident with that gap because I think if we start throwing some fire at Stephen Harper, we start to talk and connect with Canadians about the economy, sound economic management, I like where we're going."

The poll's results are based on roughly 1,300 interviews over the telephone with Canadians of voting age over the past four days and are considered accurate to within plus or minus 2.6 percentage points, 19 times out of 20.

The Harris/Decima poll is interviewing roughly 300 Canadians every night, as part of a rolling nationwide survey that will continue throughout the election campaign.

The results are released at regular intervals to track possible changes in Canadians' attitudes and loyalties.