The chairman of the Historical Institutional Abuse Inquiry said he was not in favour of extending the inquiry's remit beyond the institutional setting, on 26 September 2012.
Sir Anthony Hart heads the inquiry that will examine allegations of abuse at children's homes, care institutions and borstals between 1945 and 1995.
He told the OFMDFM Committee that changing its terms of reference to include foster care, schools or families would require a complete restructuring of the inquiry.
It would take much more time and money to complete, he explained.
Colum Eastwood of the SDLP asked Sir Anthony what he thought of extending the remit of the inquiry to cover the years before 1945.
"We have no problem with the starting-date being altered from 1945," he replied.
Sir Anthony said the people involved "seemed to be quite a small number and they seem to us to have made a compelling case".
Committee chairman Mike Nesbitt asked about the possibility of the inquiry producing an interim report.
Sir Anthony said he was opposed to this.
"Producing interim reports will mean coming to a decision before we have received all the evidence," he said.
Mr Nesbitt also asked about potential criminal proceedings.
Sir Anthony said the inquiry was prohibited from making comments regarding civil or criminal proceedings, and that the findings of the inquiry would not be admissible as evidence.
He said the inquiry was alert to the possibility that people might say things to them that indicated criminal offences may have taken place.
Sir Anthony said the panel would make this known to the police where it was their legal duty, adding that they had already discussed the matter with the PSNI.
The committee was briefed by OFMDFM officials on the department's preparations for the abuse inquiry.
Maggie Smith told members the First and Deputy First ministers had announced that the inquiry's Acknowledgement Forum would begin work on 1 October 2012.
She said the estimated cost of the inquiry was £15m to £19m.