The Public Accounts Committee has been told it cannot release the salaries of senior managers at the Rehab Group.
TDs have been given legal advice that they have no right to release information which was submitted by Rehab in confidence.
They have also been told that the head of the HSE, Tony O'Brien, gave an incorrect account of the law when he said he had no option but to release the figures.
The managers had refused to reveal their salaries at the PAC's meeting yesterday, but the HSE said it had the data and could be legally forced to reveal it.