The Commission of Investigation into the care of 'Grace' has met the vulnerable young woman and has begun hearing from witnesses, according to the commission's Interim Report, which has been seen by RTÉ's This Week.
The commission said requests for documents and statements from witnesses are being met with "varying degrees of compliance".
The age and health of important witnesses, as well as death of other key figures, are "not insignificant challenges" to the commission's work, according to the report.
'Grace' is a vulnerable young woman with an intellectual disability who in 1989 was placed with a family around whom abuse allegations were raised.
She remained in the home until 2009, despite a 1995 decision by the South Eastern Health Board (SEHB) to cease using the family for placements and to remove other vulnerable young people.
Farrelly Commission Terms of Reference
The report of the commission chaired by Marjorie Farrelly SC also says it is at "an advanced state of readiness" to look into events in 1996 - a key period of Grace's care - in early 2018.
At an SEHB meeting in early 1996, it was initially decided to remove Grace from Family X's care.
That decision was overturned at a meeting of key professionals in October of that year, for reasons that other reports have been unable to establish.
The commission will examine the decision-making at these meetings.
In 1996, Mr X, the father in the family at the centre of the allegations, and another individual wrote to the then health ministers Michael Noonan and Austin Currie.
This correspondence is also being looked at under Modules 3A and 3B, which is examining whether this correspondence had the effect of keeping Grace in the care of Family X.
The Farrelly Commission has already heard from 13 witnesses on Module 3A, which deals with the attempts by Mr X to have the initial 1996 decision to remove Grace from the home overturned.
The commission appears to have interviewed all relevant parties who were available, as it does not "at this stage anticipate taking further evidence on module 3A".
Module 3B will examine whether Mr X's contact with the Department of Health "had any impact on any decision or decision-making process in respect of Grace".
Witnesses will be heard on this early in 2018.
Mr Noonan previously denied acting in any way on behalf of Mr X on foot of his correspondence.
The interim report says significant progress has been made on Module 1, dealing with how the family with whom Grace was placed came to be used.
The commission is due to hear evidence on this shortly.
The commission will also be hearing soon from witnesses on Module 2.
This covers the period 1989-1995 and the level of monitoring of the family with whom Grace was placed was subjected to.
The module covers the level of awareness within the South Eastern Healthboard (now the Health Service Executive) of allegations made against the family with whom Grace was placed.
It will also examine whether information about Grace was shared among relevant professionals, including gardaí and what action, if any, was taken on foot of any concerns.
The Farrelly Commission Report says relevant people are being written to under Section 16 of the Commission of Investigations Act (2004), which gives the commission powers including those to compel witnesses to attend or make statements.
Under S16, the commission is also asking witnesses to identify documents in their possession or power, verified by affidavit and also to identify documents which witnesses object to producing before the commission.
The commission says that "this has been met with varying degrees of compliance".
To date, significant volumes of documentation - 280,000 pages - have also been received by the commission.
The report says that the commission needs to retain appropriate levels of staff to scan and enter the documentation in databases.
The commission says it is actively corresponding with 14 teams of solicitors.
