The Public Accounts Committee has decided to seek compellability powers for the attendance of former Rehab chief executive Angela Kerins and former board member Frank Flannery in its examination of the spending of public monies.
An application to the Dáil Committee on Procedures and Privileges is expected to be made within days.
It emerged yesterday evening that Mr Flannery and Ms Kerins had written to the PAC.
Ms Kerins said she has complained to the Committee on Procedure and Privileges concerning the way she was treated at her previous PAC hearing.
Mr Flannery raised legal issues on the remit of the PAC.
Mr Flannery's solicitors told the PAC he will neither accept nor decline an invitation to appear before the PAC until he gets a formal legal invitation outlining the issues to be addressed.
Ms Kerins's solicitors said she is still recovering and is not well enough to attend as a witness at this time.
They said this should not be construed as a refusal to attend when she is well enough.
PAC members had a discussion this morning about the letters the committee received.
Committee Chairman John McGuinness said it was clear from the tone of both letters that they do not accept that the PAC has any entitlement to examine how public monies made available to Rehab were spent.
Mr McGuinness said that it now appeared that the committee needs the power of compellability to get Ms Kerins and Mr Flannery to attend.
Sinn Féin's Mary Lou McDonald agreed with him and described the arguments put forward by Ms Kerins and Mr Flannery as bogus and designed to stall proceedings.
Fianna Fáil's Sean Fleming said he took total offence to remarks in the letters that members of the committee had abused their powers.
He described the comments as the most blatant attempt to block the committee's work.