Canadian Prime Minister Justin Trudeau has urged Pope Francis to visit Canada and issue an apology to the indigenous people over the Catholic Church's role in a school system where aboriginal children were abused for decades.

Trudeau has pledged to completely accept the government's failure in not acknowledging the century-long "dark chapter" in the country's history.

The Canadian PM was in the Vatican on Monday, 29 May, as part of his trip to Italy for the G7 summit. "I told [the pope] how important it is for Canadians to move forward on real reconciliation with the indigenous peoples and I highlighted how he could help by issuing an apology," Trudeau told reporters.

The residential schools were set up to take children away from their families and incorporate them into mainstream Canadian society. They were typically run by Christian churches on behalf of Ottawa from the 1840s to the 1990s. The last one closed in 1996.

The Truth and Reconciliation Commission (TRC) report, which was released in December 2015 after interviewing families of victims, states that around 150,000 were forcibly sent to live in church-run boarding schools, where they were forbidden to speak their language or practise their own culture.

The torture was so cruel that many endured physical and sexual abuse. At least 3,201 student lost their lives at the schools. The report also said that it was possible that many more deaths went unrecorded.

The TRC, which has called the residential school system "cultural genocide", asked for a papal apology as part of a national reconciliation framework to heal the sufferings of the survivors.

The Vatican has not commented on the development, but said that the meeting with Trudeau was "cordial" and lasted about 36 minutes.

It added that the talk "focused on the themes of integration and reconciliation, as well as religious freedom and current ethical issues" but did not directly mention about the apology.

Pope Francis with  Justin Trudeau
Pope Francis (R) walks with Canadian Prime Minister Justin Trudeau at the end of a private audience at the Vatican on 29 May, 2017 ETTORE FERRARI/AFP/Getty Images