The Commission of Investigation examining the issue says the shocking discovery was made in 17 of 20 underground chambers intended to be used as part of a sewage system.
Tests on a sample of the remains have dated to them to the 1950s – when the mother and baby home was in operation.
Children's Minister Katherine Zappone says the discovery is not unexpected, but is still deeply disturbing and must be appropriately responded to.
Sinn Féin's spokesperson on children Donnchadh Ó Laoghaire, says this is an indictment of Ireland at the time.
He's to ask the Oireachtas Children's Committee to invite the commission chair Judge Yvonne Murphy in – to ensure the terms of reference are adequate to uncover all the evidence in Tuam and at other homes around the country.
