Canada named Mary Simon on Tuesday as its first indigenous governor general -- Queen Elizabeth II's official representative in the Commonwealth country -- as the nation faces a reckoning with its colonial history.

"Today, after 154 years, our country takes a historic step," Prime Minister Justin Trudeau Trudeau told a news conference. "I cannot think of a better person to meet the moment."

Simon, a former journalist and advocate of Inuit rights, has previously served as president of Inuit Tapiriit Kanatami, Canada's national Inuit organization.

She was also president of the Inuit Circumpolar Conference, which represents Inuit in all Arctic countries.

Her appointment as viceregal representative, responsible for giving royal assent or making acts passed by parliament law and heading Canada's military, comes at a difficult period in the country's relations with First Nations.

The discovery of more than 1,000 unmarked graves at former indigenous residential schools has convulsed Canada, provoking anger and grief in indigenous communities.

Until the 1990s, some 150,000 Indian, Inuit and Metis youngsters were forcibly enrolled in 139 residential schools run by the Catholic church on behalf of the government.

More than 4,000 students died of disease and neglect.

Others have recounted physical and sexual abuses by headmasters and teachers who stripped them of their culture and language.

Simon replaces former astronaut Julie Payette who resigned in January amid accusations of harassment, and behavior described in a report as "yelling, screaming, aggressive conduct, demeaning comments and public humiliations."

Canada's supreme court chief justice had taken over the mostly ceremonial role in the interim.