Trudeau, who swept to office in November 2015 faces an electorate more focused on the economy and affordability when it votes on Oct 21.
Canadian Prime Minister Justin Trudeau kicked off a six-week re-election campaign Wednesday and immediately faced new questions about an ethics scandal that could undermine support for his Liberal Party.
Trudeau, who swept to office in November 2015 promising "sunny ways" and stressing the importance of gender equality and the environment, faces an electorate more focused on the economy and affordability when it votes on Oct 21.
"We have a huge amount of work still to do ... under a Liberal government, Canada will continue to move forward," he told reporters after launching the race.
Not since 1935 has a Canadian prime minister who won a parliamentary majority in his first term been booted from office in the next election.
But polls strongly suggest Trudeau may not win enough seats to govern by himself after a series of missteps that called into question his leadership while cutting into his once sky-high popularity. That would leave him weakened, relying on opposition members of parliament to push through legislation.
Last month, a top watchdog ruled the prime minister had breached ethics rules by pressuring the former justice minister to ensure a major construction firm avoid a corruption trial.
The Royal Canadian Mounted Police are probing whether there is enough evidence to lay charges. The Globe and Mail said Wednesday that Ottawa was limiting what potential witnesses could say.
Trudeau side-stepped repeated questions about the matter Wednesday, repeating the government's line that witnesses already had plenty of freedom to speak.
Andrew Scheer, leader of the official opposition Conservative Party, said the Globe and Mail report showed Trudeau could not be trusted.
"He has lied. He has looked Canadians in the eyes and said things that he knew were not true," he told reporters.
A Nanos Research poll released Tuesday showed the Liberals at 34.6% and the Conservatives at 30.7%. That margin would not be enough to guarantee a majority of seats in the House of Commons.
Trudeau, the son of former Liberal Prime Minister Pierre Trudeau, has broken major campaign promises by scrapping plans to introduce voter reform and allowing budget deficits to mushroom. He also angered environmentalists by buying an oil pipeline to ensure crude exports could increase.
"For average Canadians, the key takeaway ... is that Justin Trudeau is not an exception, he's like other politicians," said Nanos.
Liberals cite near-record low jobless numbers, booming growth and lower levels of poverty as grounds for re-election.