The NDP will ask Thursday that the House of Commons call on the government to apologize for breaking its promise to implement electoral reform.
The motion, which MPs will spend Thursday debating, suggests that "in the opinion of the House, the government misled Canadians on its platform and Throne Speech commitment 'that 2015 will be the last federal election conducted under the first-past-the-post voting system,' and that the House call on the government to apologize to Canadians for breaking its promise."
Democratic Institutions Minister Karina Gould announced last week that the Liberal government would no longer pursue its commitment to replace the current electoral system in time for the 2019 election.
The minister cited a lack of consensus on the issue, but the prime minister and a senior Liberal subsequently pointed to concerns about moving to proportional representation and holding a referendum.
"We know that Mr. Trudeau was elected on the promise to alleviate and diminish cynicism in our politics," NDP critic Nathan Cullen told reporters on Wednesday. "Well, he's in fact made the promise worse by conducting himself so casually with his promises."
New Democrats have since directed supporters to a petition, filed with the House of Commons, that has now received more than 80,000 signatures.
The NDP motion would likely come to a vote next week.