Ireland’s Taoiseach will apologise to survivors of homes for unmarried mothers and their children later.
The institutions for those who fell pregnant out of wedlock produced high levels of infant mortality, misogyny and stigmatisation of some of society’s most vulnerable, an independent report said.
Many mother and baby homes were run by Catholic nuns.
The commission of investigation report found “appalling” levels of death amongst the very youngest, more than one in 10 of children present.
Micheal Martin is to deliver the public acknowledgement on behalf of the State in parliament, the Dail, in Dublin later on Wednesday.
On Tuesday he said the scandal over many decades was a dark chapter in the country’s history.
He added that the Republic had displayed a “warped” attitude to sexuality and intimacy in the past.
Some of the institutions were owned and run by the local health authorities – the county homes, Pelletstown, Tuam and Kilrush.
Others were owned and run by religious orders, for example the three homes run by the Congregation of the Sacred Hearts of Jesus and Mary – Bessborough, Sean Ross and Castlepollard (the Sacred Heart homes).
The head of the Catholic Church in Ireland, Archbishop Eamon Martin, has apologised to survivors.
Some of the homes were in very poor physical condition.
Many of the women did suffer emotional abuse and were often subject to denigration and derogatory remarks, the commission of investigation’s report said.
Almost 9,000 children died, approximately 15% of all youngsters who were in the institutions, the investigation found.
Major causes included respiratory infections and gastroenteritis.
The proportion of women admitted to such homes in Ireland was probably the highest in the world in the 20th century, the Commission of Investigation into Mother and Baby Homes said.
There were about 56,000 unmarried mothers and 57,000 children in the 18 mother and baby homes and county homes investigated.