Prince Charles and Camilla are visiting the Commonwealth realm on a three-day trip to mark the Queen's Platinum Jubilee.

Charles is expected to speak about the Queen's "profound affection she feels for Canada and its people", but there are also high expectations on the royal couple to acknowledge the treatment of indigenous people, especially through the state-sponsored residential schools system.

Last year hundreds of human remains were found in unmarked graves at former church-run schools.

More than 150,000 indigenous children were forcibly separated from their families in what investigators called "cultural genocide" in 2015.

From the late 19th century to the 1970s they were sent to Christian boarding schools, where many were physically abused, raped and malnourished, had their long hair cut and were beaten for speaking their native languages.

Thousands of children died of disease and other causes, with many never returned to their families.

Last year statues of Queen Victoria and the Queen were pulled down in Canada during protests against the country's treatment of indigenous people.

Charles and Camilla will take part in a "solemn moment of reflection and prayer" within hours of landing in the city of St John's in the province of Newfoundland and Labrador at a garden dedicated to victims of the system.

The Canadian government formally apologised for the system in 2008.

Chris Fitzgerald, deputy private secretary to the prince for foreign affairs, said the couple "will first take part in a solemn moment of reflection and prayer at the Heart Garden... with indigenous leaders and community members in the spirit of reconciliation

"Heart Gardens are in memory of all indigenous children who were lost to the residential school system, in recognition of those who survived, and the families of both."

Mr Fitzgerald said: "Throughout the tour, their royal highnesses will take the opportunity to continue to engage with indigenous communities."

Their tour of Canada comes after recent criticism during other royal overseas visits.

Both the Duke and Duchess of Cambridge and the Earl and Countess of Wessex were greeted by campaigners calling for the Royal Family to apologise for the atrocities of the slave trade on their trips to the Caribbean.

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Elements of William and Kate's tour were also criticised for appearing outdated and too colonial.

Since Barbados cut ties with the royal family in November there has also been increased interest in whether other Commonwealth realms will follow suit.

Although 55 per cent of Canadians are supportive of remaining a constitutional monarchy as long as the Queen reigns, that figure drops to 34 per cent for the same arrangement under "King Charles", according to recent research by the Angus Reid Institute.