Poilievre launched a day of ministerial press conferences to remind Canadian parents they're getting money back from the government — albeit money that will be taxed next spring.
But he raised questions about the appropriateness of his clothing choice when he sported a Conservative Party T-shirt to a Canadian government event.
Canada has strict rules about using partisan logos at government events to prevent a governing party from using taxpayer money to promote itself.
Civil servants are instructed to inform the public about policies and programs "in an accountable, non-partisan fashion," according to rules set out by the Treasury Board, which sets rules for Canada's federal bureaucracy.
"[Government] Institutions must not participate in, or lend support to, partisan events organized for political party purposes," according to the rules.
Poilievre's spokeswoman didn't immediately respond to a request for comment.
The release regarding Poilievre's press conference, as well as a series of other MPs promoting the benefit, was produced by the federal government and not the Conservative Party.
Monday isn't the first time Poilievre has been criticized for using government resources for partisan ends.
Last May, the Globe and Mail reported Poilievre used public servants from his department to shoot video of him meeting constituents, which was subsequently used in a partisan video.
Despite criticism in question period over the taxpayer-funded overtime, Poilievre was unrepentant.
"I make no apologies for informing parents of the expanded universal child-care benefit," he said at the time."
NDP treasury board critic Mathieu Ravignat, a former federal public servant, called the T-shirt inappropriate, and said there's a time to be a minister, and a time to be a cheerleader for one's party.
"This blurs the clear line between ... [the] partisan nature of an event and the public service, and its need to be objective," Ravignat said.
Liberal MP Adam Vaughan said it's a clear violation of the rules.
"Are they going to have a Conservative logo on the tax bill you get sent when they claw this benefit back? My guess is no," he said.