A safeguarding review has uncovered evidence of more than 100 alleged child abuse cases at Scouting Ireland, the Irish Children's Minister said.
Katherine Zappone told a parliamentary committee that an audit by an independent consultant had found evidence of 71 alleged abusers and 108 alleged victims between the 1960s and 980s.
Ms Zappone said Ian Elliott's review of historical records is "based on his work to date and the numbers may change".
She added: "It is devastating. I find it extremely distressing as the minister to have received that information."
She told the committee on children and youth affairs on Wednesday morning that she had been informed of the cases on Tuesday night and that files had been sent to the Garda and child protection agency Tusla in respect of the alleged abusers who are still alive.
She said she understood none of the alleged abusers were still working with the scouting organisation.
The review is not yet complete.
Committee members said they were "shocked" and "aghast" at the findings.
Fine Gael TD Tom Neville said like every other member of the committee he was "aghast" at the revelations.
"I welcome the fact that this information has been found and that it is coming out. I don't welcome the fact that it actually happened," he said.
He added that it was important the truth came out to ensure it did not happen again.
Labour TD for Cork East Sean Sherlock described the details as "devastating" and said the committee should empathise victims who are traumatised by the revelations.
He added that honest volunteers would also be "devastated" and "traumatised" by the revelation.
"It really is shocking. I have to say I'm absolutely viscerally shocked by this information," he said.
Mr Sherlock also said a mechanism needed to be found to ensure historical cases were dealt with and also that scouting could continue "safely and without a cloud hanging over it".
Ms Zappone acknowledged the "extraordinary work" that does go on in the organisation.
"I've seen that first-hand throughout the country and the work that's gone on in supporting the children and young people and the volunteers and how important that is," she said.
"I want to assure people that I want to continue to support that."
But she said that given the information, she would be monitoring the situation and funding would not be fully restored until issues were resolved.
Scouting Ireland chairwoman Aisling Kelly apologised for the "hurt" caused as a result of "poor practice".
"When we last appeared before this committee, an apology was offered for the hurt that has been caused as a result of poor practice on the part of those involved in scouting. Some of this occurred many years ago but the effects are still causing distress today," she told the committee.
"I want to reiterate that apology and add to it our sincere regret for what has happened, and our absolute determination to learn from those mistakes and make Scouting Ireland today as safe an environment as we can create for all of our members."
Ms Kelly said the organisation had undergone a "radical governance change" and was "working hard" to establish the full extent of the knowledge that exists in relation to the abuse.
"Personally, as a mother of two very young children, this fills me with deep sadness," she said.
"I want to say categorically that Scouting Ireland is committed to providing support and help to all victims of past abuse within scouting."
A new board was elected for Scouting Ireland last month.