The Banking Inquiry whistleblower says they 'categorically refute' the findings of an independent investigation into their claims and will consider taking legal action.
The report by Barrister Senan Allen has yet to be published by the Houses of the Oireachtas but the whistleblower has been given a copy.
In a statement to the Irish Independent, the whistleblower, who worked for the inquiry's investigation team took issue with a number of findings.
Central to their complaint is the claim other inquiry staff who raised concerns about the investigation were not interviewed by Mr Allen.
"My decision to come forward as a Whistleblower was not taken lightly. My reason for doing so is that I had, and continue to have, serious concerns about the manner in which the banking inquiry is being conducted," the statement reads.
It adds:"It is in that context that I would like to respond to Mr Senan Allen’s report on the operation of the investigation team.
"I categorically refute the conclusions of the report and I have grave concerns about the manner in which Mr Allen’s investigation was conducted."