The Cabinet has approved a draft order which includes the revised terms of reference setting out the work of the commission of investigation into the 'Grace' case.
It will be brought before the Dáil tomorrow, when it is expected there will be short debate.
The commission is holding an investigation into a foster care home in the southeast.
The investigation will be carried out in two phases.
The first phase will mainly centre around 'Grace'. At the end of phase one, a report will be brought to Government specifying further investigations to be carried out.
The phase two investigations will centre around the care and decision making in respect of the other 46 individuals that passed through the home and the treatment of the whistleblowers.
Earlier, the Minister of State with responsibility for Disabilities said he would circulate revised terms of reference in the inquiry after criticism that the terms of reference outlined yesterday were too narrow.
Finian McGrath said no one would be excluded from the investigation.
Initially, the inquiry was to focus on what happened to a young woman with intellectual disabilities, known as 'Grace', who was left in a foster home in the southeast for almost 20 years despite a succession of sexual abuse allegations.
Families of other service users of the foster home expressed concerns that their cases would not be examined promptly in the inquiry.
On 'Grace' inquiry, McGrath says: 'I will include everybody and let their voices be heard. I don't do exclusion. pic.twitter.com/L7Gam73SSF— RTÉ News (@rtenews) March 8, 2017
During Leaders' Questions, Taoiseach Enda Kenny said Mr McGrath would come back to the House with amended terms of reference tomorrow, adding that there was no reason to delay the work of the commission.
He was responding to Fianna Fáil leader Micheál Martin, who said three issues needed to be addressed in the terms of reference: the inclusion of others in the home; the treatment of whistleblowers; and the timeline.
Mr Martin said the first whistleblower went back to 1992 and the timeframe suggested was not acceptable.
He also said it was "stretching credulity" that only one person was abused.
The Taoiseach said that Minister McGrath wanted to get the terms right and wanted to make it clear there is a phase one and phase two to the inquiry.
It has also emerged that a young woman with intellectual disabilities continued to visit the 'Grace' foster home in the southeast up until 2015.
Minister for Communications Denis Naughten said he is confident the new terms of reference will reflect many of the opinions in the Dáil.
Speaking on RTÉ's News at One, Mr Naughten said there was no one more up to speed on the issue than Mr McGrath, who has pressed for the actions that have taken place to date.
He said people need to be held accountable what happened to 'Grace', which Mr Naughten said was "absolutely disgusting".
The head of children's charity Barnardos had earlier described the terms of reference outlined yesterday as "inexcusable and appalling and inexplicable".
Barnardos CEO Fergus Finlay said not all of the stories have been heard and there are other families "of great courage" who have fought for their children for several years and deserve to have an investigation into their cases as well.
Speaking on RTÉ's Morning Ireland, Mr Finlay said they deserve justice, regardless of the cost.
"These are Irish citizens we are talking about. They're not nameless, faceless people. They've been damaged on the State's watch.
"If it does cost money to find out what happened and why it happened and whether or not it could have been prevented - we have to spend that money. We would do it for any other Irish citizen.
"Why, when it comes to the most defenceless Irish citizens, do we say it's all a matter of money?", he asked.
During statements in the Dáil on the inquiry this morning, Fianna Fáil TD John McGuinness pleaded with Minister McGrath to amend the terms of reference on the 'Grace' inquiry.
Mr McGuinness said accepting the terms of reference as they were, would heap further abuse on families.
Fine Gael TD John Deasy said he and Mr McGuinness discovered the first casualty was always the truth when dealing with the HSE on the issue.
Labour TD Jan O'Sullivan has also called for the terms of reference to be widened, saying a mechanism needed to be found to ensure the terms were as comprehensive as they needed to be.
Sinn Féin TD Imelda Munster said the commission of investigation had to deliver accountability, which she said has been missing all along. She said it was not a systems failure but the failure of individuals.
Ms Munster asked who was responsible at the top of HSE management and why no one was ever charged.
"It will not be worth the paper it's written on if you don't go hell bent on stamping out the culture of unaccountability which is rife in HSE top management", she said.
Independents4Change TD Catherine Connolly said it was difficult to stand in the Dáil on International Women's Day to talk on such a topic.
While she acknowledged the need for an inquiry, she said she could not agree to the motion on the commission of investigation into the 'Grace case'.
Green Party leader Eamon Ryan, who has a child with disabilities, said his family's experience was not a positive one regarding the State's psychological services.