Canada's parliament on Tuesday elected Greg Fergus as its first black speaker, following his predecessor's resignation over the public celebration of a Ukrainian veteran who fought for the Nazis.

Fergus, a Liberal MP, said the Commons is where "hard debates will happen," but urged lawmakers to "treat each other with respect."

"There can be no dialogue unless there is a mutual understanding of respect."

As speaker of the chamber, his role is to chair House of Commons debates and enforce parliamentary rules while remaining impartial, only voting to break ties.

Fergus was escorted arm in arm into the House of Commons by Prime Minister Justin Trudeau and opposition leader Pierre Poilievre, as is tradition.

Congratulating him for being the first Black Canadian to become speaker, Trudeau said: "This should be inspiring for all Canadians, especially younger generations who want to get into politics."

First elected as a member of Parliament in 2015, Fergus founded the parliamentary black caucus. He also served as Trudeau's parliamentary secretary.

His new role as speaker must start with "restoring the honor of this chamber," Jagmeet Singh, the leader of the New Democrats said.

During a recent visit to parliament by Ukraine's President Volodymyr Zelensky, the former speaker, Anthony Rota, had hailed an elderly Ukrainian immigrant from his district as a hero, prompting a standing ovation.

He resigned after it was revealed that the veteran had served in a Nazi-linked military unit.