OTTAWA - The Liberals were showing signs of recovery as the Conservatives held on to a sizable -- but shrinking -- national lead in recent days, a new poll suggests.

A Canadian Press Harris-Decima poll taken over the last four nights put the Conservatives at 37 per cent support -- a two-point drop over the last few days -- while the Liberals climbed to 24 per cent, a one-point increase over Monday's figures.

The survey has the New Democrats and Bloc Quebecois steady at 17 per cent and eight per cent respectively, while the Green party is down one point at 11 per cent.

All of the changes remain well within the poll's margin of error.

"In the national numbers, I think we can say that the deterioration for the Liberals has stopped. They may have hit a floor," said Harris-Decima president Bruce Anderson.

"In some parts of the country, among some segments of voters, there's a little bit of evidence that they're recovering a bit."

Meanwhile, speculation about a possible Tory majority may have spooked some voters into switching sides, Anderson said.

Prime Minister Stephen Harper's positive impression among voters has also started to dip from its peak at the beginning of the campaign, he added.

The numbers suggest voters are split in their impression of Harper over the last four days -- 45 per cent of respondents reported an unfavourable impression of the leader, while 44 per cent said their impression was favourable.

"That's probably a function of the Conservatives putting less of their advertising weight around Stephen Harper and the positive image that they've created about him, and more around their criticisms, if you like, of other parties' platforms and leaders," Anderson said.

"And also the fact that other parties are doing a fair bit of campaigning against Stephen Harper."

The poll surveys 300 people a night in a rolling national sampling and the figures are based on interviews with 1,232 people Friday through Monday.

The results are considered accurate to within plus or minus 2.8 percentage points, 19 times in 20.

Regionally, the Conservatives still lead the Liberals in every part of the country, although they trail the Bloc in Quebec.

But the race seems to be tightening in Ontario, with the Liberals nearly neck-and-neck with the Tories. The poll puts the Conservatives at 35 per cent support and the Grits at 34 per cent, while the NDP are sitting at 16 per cent and the Greens at 12 per cent.

Because of the smaller sample size, the margin of error for regional or demographic breakdowns is significantly larger than it is for overall percentages.

More information on the poll is available from www.harrisdecima.com. Respondents to the poll were asked the following question: "If a federal election were being held tomorrow, who do you think you would be voting for in your area?"