Voting-age Canadians rate Prime Minister Stephen Harper as the most competent and trustworthy federal political leader, but a new poll suggests Liberal Leader Bob Rae is making the most gains with the electorate.

A Nanos Research poll conducted for CTV and The Globe and Mail found that 30.4 per cent of surveyed voters picked Harper, when asked to name the most trustworthy leader.

In this category, Harper ranked ahead of Liberal Leader Bob Rae (16.3 per cent), NDP Leader Nycole Turmel (11.2 per cent) and Green Party Leader Elizabeth May (10.5 per cent).

About one in seven Canadians surveyed said they were undecided (16.3 per cent), while a similar percentage (15.3 per cent) said that "none of them" were the most trustworthy.

The same group of Canadians was asked to rank who was the most competent federal leader. Here, Harper also led the pack with 37 per cent, placing him ahead of Rae (18.3 per cent), Turmel (6.8 per cent) and May (3.9 per cent).

One in five people (21.5 per cent) said they were undecided, while 12.4 per cent answered "none of them" in response to the competency question.

Nearly 3 in 10 people who took part in the Nanos survey (29.8 per cent) said Harper also had the best vision for Canada, while about half as many respondents (15.3 per cent) picked Rae.

Ranking third on the vision question was Turmel (13.3 per cent), followed by May (6.6 per cent). About one in five people (21.2 per cent) said they were undecided, while 13.8 per cent said none of the leaders had the best compelling vision.

Nanos also released its latest Leadership Index Score, a measure that adds together the percentages each leader received from voters who believed they were the most competent or trustworthy leader, or had the best vision for Canada.

Harper received a leadership index score of 97.2, which was down from 114.2 in the previous month.

Rae had a score of 49.9, which was well behind the prime minister, but up more than 10 points from September.

Turmel fell from 34.5 in September to 31.3 in October, while May jumped from 12.5 to 21.0 in the leadership scoring.

The Nanos poll was conducted between Oct. 20 and Oct. 24, a time period in which 1,202 voting-age Canadians were asked about the federal leaders. It is considered accurate to within 2.8 percentage points, 19 times out of 20.