The Dáil's Public Accounts Committee has been told it cannot force two former CEOs of Rehab to come before it, ahead of today's meeting.
Frank Flannery and Angela Kerins can't be forced to appear, it emerged yesterday, because the Dáil's internal watchdog said Rehab does not answer to the PAC.
The issue is likely to be discussed at a private meeting of the PAC this morning.
The Dáil's powerful internal regulator - the Committee on Procedures and Privileges - voted unanimously last night that the PAC does not have the power to compel the pair to attend.
It said Rehab doesn't fall under the direct financial supervision of the state, and therefore it cannot allow the PAC to call in executives to answer questions about a private entity.
The PAC had argued that Rehab was using public money to subsidise its business operations, which in turn pay for salaries far in excess of the public pay cap.
However the PAC has been given the consolation of being allowed to compel three other people to take questions on a separate investigation, into the questionable use of a HSE training fund worth over €4 million.
The PAC is due to hold a private hearing this morning, and the question now is whether it will mount an outside legal challenge to force Angela Kerins and Frank Flannery to appear.