A new poll says 29.5 per cent of Canadians think Stephen Harper is the best federal party leader to be prime minister. That's far ahead of Michael Ignatieff, who came in second at 17.3 per cent.

However, in a separate question, the survey also says a third of voters are unsure which leader -- if any -- is trustworthy or competent.

The Nanos Research survey suggests Canadians are largely disappointed with the level of discourse on Parliament Hill.

When respondents were asked which party leader would make the best prime minister, here are the full results (difference from a February poll in brackets):

  • Stephen Harper, Conservative: 29.5 per cent (-1.1)
  • Michael Ignatieff, Liberal: 17.3 per cent (+1.2)
  • Jack Layton, NDP: 15.6 per cent (-2.5)
  • Gilles Duceppe, Bloc Quebecois: 6.3 per cent (+0.5)
  • Elizabeth May, Green Party: 5.5 per cent (-1.4)
  • Unsure: 14.5 per cent (+5.1)
  • None of them: 11.3 per cent (-0.4)

Pollster Nik Nanos said Harper's numbers have dropped because of a number of recent issues he has had to deal with on Parliament Hill, including the Helena Guergis-Rahim Jaffer problem, the Afghan detainee issue and the G8 maternal health and abortion plan.

"The good news for the prime minister is that he has a comparative advantage over Michael Ignatieff and Jack Layton, it's just that that comparative advantage has diminished in the last quarter," he told CTV News Channel Monday.

Harper had his highest level of support in the Prairies, at 46.5 per cent, and his lowest in the traditional Liberal stronghold of Ontario, at 27 per cent.

Ignatieff, by contrast, had the most supporters in Ontario at 23.5 per cent -- but still lower than Harper. In the Prairies, just 10.9 per cent of respondents thought he would make the best prime minister.

"If you are a Liberal strategist looking at these numbers you are seeing a leader that is trailing his party," Nanos said. "For Michael Ignatieff, his leadership has been characterized by fits and starts, he hasn't seemed to been able to land a strong punch on the prime minister."

The survey also asked Canadians to choose which leader they trusted, was competent, and had a vision for Canada.

None of the leaders managed to gain more than a third of support, but Harper had the highest numbers, with 30.2 per cent saying they trusted him more than any other leader.

However, 32.6 per cent felt were undecided, or felt they couldn't trust any of the leaders.

 TrustCompetenceVision for Canada 
Stephen Harper 23.9 per cent 30.2 per cent 25.1 per cent 
Jack Layton16.8 per cent 11.7 per cent 16.3 per cent 
Michael Ignatieff11.0 per cent 15.1 per cent 14.7 per cent 
Elizabeth May6.8 per cent 2.2 per cent 5.2 per cent 
Gilles Duceppe9.0 per cent 8.2 per cent 3.9 per cent 
None / Undecided32.6 per cent 32.6 per cent 34.6 per cent 

The numbers above are from a Nanos national random telephone survey of 1,003 Canadians 18 years of age and older. It was completed between April 30 and May 3, 2010. The statistics of a random sample of 1,003 respondents is accurate to within 3.1 percentage points, 19 times out of 20.