The Public Accounts Committee will meet this evening to decide whether to seek legal powers to force Frank Flannery to appear before them.
The former Rehab chief executive has refused to attend a hearing of the committee to discuss the pay of its senior executives.
The committee last week heard that the organisation which paid Mr Flannery's salary, and that of his successor Angela Kerins, is 40% funded by the taxpayer.
PAC members will now decide whether to begin legal procedures forcing Mr Flannery to attend a hearing in future.