The Taoiseach (Irish prime minister) Mícheál Martin has said it is "regrettable" that a report into mother and baby homes was leaked to the press before those affected got to see it.
The institutions housed women and girls who became pregnant outside marriage.
They made international news in 2017 when the bodies of 796 children were found buried in the grounds of a former home in Tuam, County Galway.
Children's Minister Roderic O'Gorman said he was angry about the leak.
The Sunday Independent's coverage included an interview with the Taoiseach about the report.
It is expected to find that 9,000 children (one in seven) died in the 18 institutions investigated.
In the Dáil on Wednesday, Mr Martin is expected to apologise formally to the victims on behalf of the state and the wider society.
As a response the Irish government established an independent Mother and Baby Homes Commission.
In an interim report the commission found that some babies were buried in 20 chambers inside a larger decommissioned sewage tank.
The controversial mother and baby homes also featured in the movie Philomena starring Dame Judi Dench.
It tells the story of a woman seeking to find her son who was adopted by an American couple.