The Chair of the Public Accounts Committee says his members will be putting forward a "robust defence" against Angela Kerins' legal action.
The former Rehab CEO was yesterday granted leave to seek a High Court injunction preventing her from being called before the PAC.
Ms Kerins claims the Committee acted "unfairly and unlawfully" when she appeared before it last February - causing her to lose her job and suffer illness.
However, PAC Chairperson John McGuinness says his members were simply doing their job.
Mr McGuinness said: "We will be putting forward a robust defence of our position because we were simply doing our job in the context of examining the accounts of the HSE and the other departments relative to the spending of public money.
"This is not about Angela Kerins or Frank Flannery, this is about the Public Accounts Committee seeking the information regarding that spend."