Fianna Fáil says if Frank Flannery refuses to appear before the Public Accounts Committee then the Taoiseach needs to remove him from a Government-appointed post.
Pressure remains on the now former Rehab director and advisor to Fine Gael to come before the taxpayers' watchdog.
One Government Minister, Labour's Pat Rabbitte who is a long-time friend of Mr Flannery, says he believes he will answer questions at PAC without being compelled to do so.
Fianna Fáil's Seán Fleming says if Mr Flannery doesn't answer questions then they will press the Taoiseach to remove him as chair of the Government-appointed forum on philantropy.