Canadians quickly warmed to Justin Trudeau when he was elected leader of the federal Liberals last April, and a new poll suggests he continues to score top marks for trustworthiness and his vision for Canada.

But the survey released on Thursday by Nanos Research also suggests Mr. Trudeau is not considered particularly competent, and the high levels of support enjoyed by his party likely stem more from dissatisfaction with Prime Minister Stephen Harper and the Conservatives than from the Liberals' own performance.

The new survey was completed on Aug. 22, when Mr. Trudeau's call for legalization of marijuana was making headlines. But "just six people out of 1,000 said that [marijuana] was the top national issue of concern," said Nik Nanos, the president of the polling firm.

Story continues below advertisement

Corruption and the scandal over Senate expenses were major concerns among the respondents, second only to jobs and the economy. So Mr. Trudeau and the Liberals should "not be smug," Mr. Nanos said, "because the research suggests that the current political situation is more a result of the Senate controversy than anything else."

The Liberals had the support of 35.7 per cent of decided voters, giving them a comfortable six-point lead over the Conservatives at 29.5 per cent. That echoes other recent polls and is not much different from the Nanos voter survey conducted in June.

The New Democrats, who have topped 30 per cent in popular support twice since 2011 – including once after the election of Thomas Mulcair as leader – dropped to 24.8 per cent. The Greens were at 5.5 per cent. And the Bloc Québécois was at 15.5 per cent in Quebec, well behind the Liberals with 35 per cent and the NDP at 29.6 in that province. The Conservatives stood at 14.8 per cent.

Nanos recruited 1,000 Canadians by telephone to provide their opinions online, and the national results are expected to reflect the views of the broader public accurately within 3.1 percentage points 19 times in 20.

In terms of leadership, Mr. Harper's overall numbers were better than those of Mr. Trudeau and Mr. Mulcair. But they were elevated by the good marks the respondents gave him for competence, a trait Mr. Nanos said is generally assumed of a sitting prime minister.

In contrast, Mr. Trudeau was named the most competent leader by just 17.4 per cent, but he edged Mr. Harper when those surveyed were asked which leader was most trusted, and he was four points head in terms of his vision for Canada.