The whistleblower at the centre of the Grace foster care abuse case has said she does not believe there is "any evidence" to suggest failures on behalf of Michael Noonan.
The whistleblower said she had seen much of the documentation held by the Department of Health in relation to the case during the 1990s, when Mr Noonan was health minister.
She said that if she did believe Mr Noonan was culpable, she would call on him to resign.
"I see no evidence that Michael Noonan interfered with, or indeed that he ever sought to interfere in this case," the whistleblower told RTÉ's 'This Week' programme.
"I don't think there is evidence there to suggest Michael Noonan is responsible for the failings that continued to happen to Grace specifically. If I did, as you know, I'd be the first person calling on him to resign," she added.
The whistleblower said Mr Noonan should be given the opportunity to give evidence at the upcoming inquiry, which is being led by Senior Counsel Marjorie Farrelly. She added she believes there are three other health officials who were involved in decisions in relation to Grace's treatment and that it is essential they give a full account.
Mr Noonan has said he had nothing to do with the Grace case and that suggestions he should step down were "ridiculous".
The Oireachtas last week approved expanded terms of reference for the Commission of Investigation into the abuse of Grace.
The commission will examine how Grace was allowed to remain in a home in the south-east for 13 years, after allegations of sexual abuse were made against her foster father. The second part of the inquiry will examine the cases of 46 other children.