The leaking of details from the Commission of Mother and Baby Homes report is "disappointing", according to a survivor.
Minister for Children Roderic O'Gorman says it was "completely unacceptable" after details appeared in the Sunday Independent.
The final report is due before the Cabinet tomorrow, and survivors had been told they would see it first.
Chairman of the Mother and Baby Home survivors, Paul Redmond, says many were "taken aback" after reading it in the newspaper before being informed themselves.
"There has been so much communication from the Department lately, promising that we would be at the heart of everything, and we would be the first to know everything, so it was a shock that some person decided to undercut us like that.
"Everybody had psyched themselves up to see the report on Tuesday, and they have been psyching themselves up for weeks for tomorrow, and all of a sudden it's just thrown in front of you," Mr Redmond said.
On Wednesday, Taoiseach Micheál Martin is due to give a formal State apology to the survivors of the mother and baby homes, following a meeting of the Cabinet on Tuesday to discuss the report in detail and any urgent actions that need to be taken, including the immediate prioritisation of the Adoption and Tracing Bill which allows adopted children gain access to information about their birth mothers.
Following the leaking of the report yesterday, Sinn Féin leader Mary Lou McDonald described the situation as "grossly insensitive" and called on Mr O'Gorman to establish how the information was shared prior to the report's publication.