OTTAWA – As anticipation builds for the fall federal election campaign to be officially launched, a new Nanos survey indicates that Canadians are split on whether it's time for a change in government, with nearly a fifth of those surveyed saying they are still undecided.

Prime Minister Justin Trudeau has until Sept. 15 to visit the Governor General and ask for the writ to be drawn up, kicking off the formal election period that will see federal party leaders crisscrossing the country and pitching themselves, their candidates, and their platforms, before voters go to the polls on Oct. 21.

According to these new Nanos numbers commissioned by CTV News, more Canadians say they are ready for a change than those who aren't, with 44 per cent of those surveyed saying they want a change in government, and 39 per cent think not. Another 18 percent remain undecided.

The Prairie provinces were where the most respondents said that they think it's time for a change with 58.9 per cent of people saying they'd like to see a new government in Ottawa, followed by 44 per cent of Ontarians. Atlantic Canadians were the least likely to say so, with 51.5 per cent saying now is not the time for change, followed by 41.6 per cent of British Columbians.

Men were more likely to favour a new government than women; while young people aged 18 to 34 expressed the least desire for change.

Both the NDP and Conservatives are keen to kick off their campaigns, and tap into that change sentiment. With a shorter campaign on the horizon there will be about half the amount of time for them to do so, in comparison to the 2015 marathon race that was the longest federal election in recent history.

Visiting the NDP's headquarters and election war room in Ottawa on Saturday, Leader Jagmeet Singh rallied his campaign staff and volunteers, motivating his supporters for the third-placed party’s tough campaign ahead. A poster affixing one wall read: "Want different results? Make a different choice."

On CTV's Question Period on Sunday, NDP Campaign Director Jennifer Howard said that Singh will be travelling the country to reach out to as many voters as possible to spread this message, but will also be "using social media and digital advertising to reach Canadians in new ways."

The Conservatives are also already working to differentiate themselves, with a message centred on affordability.

"If you go door knocking and you talk to Canadians, they're not feeling good about the economy… people are not optimistic about their next five, 10 years," said Brock Harrison, director of communications for Conservative leader Andrew Scheer.

Though, Liberals say that is not the reception they are receiving on the ground.

"I was with the prime minister this past week and you know you can just feel the energy off of him. He loves a good campaign," Liberal MP and Ontario Campaign Co-Chair Marco Mendicino told CTV’s Question Period.

Less than 50 days out and the latest Nanos tracking has the Liberals with about a four point advantage over the Conservatives. The NDP and the Green Party are in a close fight for third place.

"It is a very tight race, so maybe we should all buckle up," Nanos said on CTV's Question Period.

Environment still top influential issue

Asked what will be the most important issue which will influence which party or candidate they vote for, Canadians most often said the environment and climate change, with 27 per cent of those surveyed bringing it up.

The Liberals, Conservatives, New Democrats and Greens have all presented their climate change plans, with each billing them as the best plan for Canada to tackle a pressing global issue.

Following the environment, here are the other top-ranking issues among Canadians:

Economy: 19.5 per cent

Integrity, trustworthiness, ethics: 8.4 per cent

Health, healthcare: 5.8 per cent

Budget, debt, spending: 4.2 per cent

Taxes: 4.1 per cent

Issues less likely to sway voters

Only 3.9 per cent of respondents said that the political leader or their party banner was the top issue influencing their vote.

Other less prominent issues on the minds of voters surveyed heading into the election include some of the topics that the leaders have been pushing arguably the hardest in the lead up to this campaign:

Immigration: 3.5 per cent

Social issues: 3.1 per cent

Cost of living, housing: 2.7 per cent

Pipelines, energy, oil: 1.9 per cent

The Liberals have been going after Scheer over his past comments and personal beliefs on social issues like abortion and same sex marriage, which in a new online advertisement the Conservative leader chalks up to "personal attacks."

Meanwhile, Scheer is pitching himself as the oil and gas sector's best choice, as Singh continues to centre housing as one of the key progressive issues he’s championing, while People's Party of Canada Leader Maxime Bernier has defended his opposition to mass immigration.

It's yet to be seen whether any of these currently less top-of-the-ballot topics in voters' minds will ascend over the course of the 43 days left between now and the election.

With a report from CTV News' Annie Bergeron-Oliver

Methodology: These results were part of an RDD dual frame (land-and cell-lines) hybrid telephone and online random survey of 1,000 Canadians, 18 years of age or older, between Aug. 29 and Sept. 4, as part of an omnibus survey. Participants were randomly recruited by telephone using live agents and administered a survey online. The sample included both land-and cell-lines across Canada.

The margin of error for a random survey of 1,000 Canadians is ±3.1 percentage points, 19 times out of 20.