The Public Accounts Committee is to seek to compel former CEO of the Central Remedial Clinic Brian Conlan to appear before them to answer questions about the top ups controversy.
Yesterday the Board of the CRC appeared before the Committee to discuss the use of donations to top up salaries and pensions of senior executives.
However Mr. Conlan, who resigned on Monday, refuse to attend.
The Minister for Health has again threatened to cut funding to the Central Remedial Clinic if it does not honour HSE pay rules.
James Reilly says the "service level agreements" can be changed to force bodies like the CRC to fall into line.
The Minister said that he will wait for a report from the HSE before he orders any action into the use of private funds to pay salaries at the CRC.
But he said that he will do whatever he can to make managers co-operate, while also leaving patients unaffected.
"We will use all available powers to us to ensure that public pay policy is adhered to, and one of those avenues open to us is the service level agreement".
"But I want to make sure it's done in a way that affects those who are in breach, and not those they're supposed to serve."