Prime Minister Justin Trudeau is expected to ask Pope Francis to issue a formal apology for the role of the Catholic Church in the residential school system.

Trudeau is expected to raise the issue during a one-on-one meeting with the Pope when he visits Vatican City on May 29, during his trip to Europe for the NATO and G7 summits.

The Truth and Reconciliation Commission included a demand for a formal apology from the Pope to residential schools survivors as one of the 94 calls to action in its report on the dark chapter in Canadian history.

The report said the apology should be delivered on Canadian soil.

"It is a conversation that is going to have to happen between the two gentlemen. Obviously, the Vatican is well aware of the TRC request and they know that's something that we will be raising, but in terms of advancing that conversation I think it's going to have to happen in the room," said Canadian government officials, speaking on background at a technical briefing for reporters ahead of the trip.

"We accepted all of the recommendations so I think you can expect that would be part of the conversation," the official said.

Trudeau has previously promised to speak to the Pope about an apology, but noted he could not compel him to agree.

The Vatican issued a statement from the previous pope, Benedict XVI in 2009, expressing sorrow for the treatment of indigenous children in residential schools.