The Public Accounts Committee has told Angela Kerins she can't have any say in the moves to force her to appear before it.
Solicitors for the former Rehab CEO have written to the committee, asking if she can have any input in the plans to seek compellability.
She has been told that the legal process involves TDs only and that she cannot have a say.
Chairman John McGuinness said that the committee might have to wait until the summer recess before a decision on whether it can go ahead with plans to force Ms Kerins and her predecessor, Frank Flannery, to appear.
He says the official application to force Ms Kerins to appear has already been lodged.
"The application for compellability is a parliamentary procedure from one Dáil committee to another Dáil committee and there is no provision whereby those who may be the subject of the compellability can have an input into that process," he said.
"That's the answer to the letter."