The HSE says it may be necessary to call the Gardaí to discuss financial arrangements at the Central Remedial Clinic.
Some €700,000 worth of charitable donations to the Central Remedial Clinic (CRC) was used to fund a retirement package for former Chief Executive, Paul Kiely, when he left the disability service in June.
This is on top of the €3m loan from the charity arm Friends and Supporters of CRC to fund the pension pot of Mr Kiely and others.
The Dail's Public Accounts Committee (PAC) has heard that Mr Kiely's lump sum payment was far greater than what he had claimed when he appeared before them on December 11.
The HSE told the committee that on top of his €200,000 tax-free payment which he disclosed to the committee, he received a €273,336 taxable sum. A further €268,689 was paid to Mercers "to ensure that Mr Kiely's pension/lump sum benefits would not be less than if Mr Kiely had continued to remain as Chief Executive until November 2016."
At the same time of this final payment, an amount of €700,000 was paid by Friends and Supporters of the CRC described as a "donation."
The information came to light when the HSE put in place an interim administrator at the CRC following the resignation of the entire board last month. According to correspondence provided to the PAC, the administrator, John Cregan, told HSE Chief Executive, Tony O'Brien:
"The payments to Mr Kiely could not have been made by the CRC if the €700,000 had not been received from the Friends and Supporters," the letter said.
The CRC board agreed the arrangement in February 2013, but also decided that a legally binding confidentiality agreement would be put in place.
Under questioning by the PAC, a board member of the PAC at the time, Brian Conlon, said he was not aware of the payments being agreed to or made. "This is completely new to me, I am surprised as anybody with what happpened," he said.
Mr Conlon, who replaced Mr Kiely as CEO before resigning in December, said: "There are no files in the office that would give reference to any of this being agreed."
Fine Gael TD Kieran O'Donnell said the information that came to light this morning was "pure dynamite" and asked that Mr Kiely will come back in before the PAC again. "It's an affront to the PAC and people who collect funds up and down the country for the CRC," he said.