OTTAWA -- Liberal cabinet minister Catherine McKenna says Canada still has credibility on the world stage as a climate change champion despite the controversy over Liberal Leader Justin Trudeau's past dressing in blackface.

McKenna, the environment minister, tried to push the fractious federal election campaign onto more familiar territory for her and her embattled party on Saturday, framing the fight against climate change as the core issue facing voters.

Trudeau had to contend with global mockery on Friday, including from late-night American comedians as images of the three times he chose to put on black- or brownface as part of costume events continued to flash around the world. U.S. President Donald Trump said he was surprised by the images of Trudeau.

McKenna promised to advocate for a ban on single-use plastics from federal government buildings, museums and parks at an event on the shores of the Ottawa River just west of Parliament Hill. The pledge was part of her local campaign as the MP for Ottawa Centre, and was not a plank in her party's federal platform.

McKenna deflected a question about whether the controversy had undermined Canada's efforts to lead globally on climate change.

"The measure of a person and of a party should be based on what you have done," she said, citing Canada's international actions to tackle climate change and "provide a leadership role at the table" as well as "action to combat racism or our announcement yesterday that we would eliminate assault weapons."

She added that "this election could not be more important," noting that issues like climate change are at stake.

"We have (a) Conservative Party and Conservative politicians who do not believe in action on climate change," McKenna said.

Trudeau wasn't campaigning Saturday and neither was Conservative Leader Andrew Scheer. Both were taking a break from the road, as is common on Saturdays during federal elections, after keeping up full-tilt schedules since the federal election call on Sept. 11.

NDP Leader Jagmeet Singh campaigned in Toronto, reiterating his commitment to help self-employed workers who are feeling left behind economically.

Singh was campaigning with Andrew Cash, a former NDP MP who's trying to take back his Davenport seat from the Liberals. They held a discussion on precarious work at a neighbourhood coffee shop.

Green Leader Elizabeth May is in Winnipeg, where she's to make an announcement in the morning and campaign with Manitoba Green candidates at The Forks later.

People's Party Leader Maxime Bernier is in northern Ontario for a plowing match and a rally in North Bay.

This report by The Canadian Press was first published Sept. 21, 2019.