Over the past four weeks the advantage enjoyed by Liberal Leader Justin Trudeau over Conservative Leader Stephen Harper on the preferred PM measure has narrowed from eight to three points.

In the latest Nanos tracking 32 per cent of Canadians would prefer Trudeau as Prime Minister while 29 per cent prefer Harper, 20 per cent Mulcair and four per cent May (14 per cent of Canadians were unsure).

Of note, NDP Leader Thomas Mulcair is near a 12 month high for his individual score on the preferred PM tracking.

On the Nanos Party Power Index as a whole, the Liberals continue to receive the highest score at 57 points out of 100, followed by the Conservatives at 52 points, the NDP at 51 points, the Green Party at 31 points and the BQ at 26 points (Quebec only).

After a very positive summer for the Liberals, their score on the index continues to slide with both the Conservatives and NDP increasing their scores on the index. For the first time since the early summer, the Liberals and the Conservatives have close index scores among male voters.

The Liberals, however, still enjoy a noticeably larger pool of accessible voters.

Asked a series of independent questions, 53 per cent of Canadians would consider voting Liberal, while 44 per cent would consider voting NDP, 40 per cent would consider voting Conservative and 27 per cent of Canadians would consider voting for the Green Party.