The chairman of the Dáil Public Accounts Committee has said that a legal challenge by former Rehab chief executive Angela Kerins to the committee's questioning of her will be robustly defended.

Speaking on RTÉ's Morning Ireland, John McGuinness said that the case had to be challenged as there was a fundamental principle at stake.

He also defended the conduct of the PAC, saying: "The Oireachtas and the Public Accounts Committee is there to carry out a particular function. 

"We carried out that function within our remit - we spoke about taxpayers' money; we were dealing with the governance and so on that arose out of Section 38 ... the agreements they had with the HSE and other agencies," Mr McGuinness said.

"Therefore we were perfectly entitled to examine the accounts. I believe that in all of this that the members treated fairly all of the witnesses that came before us," he added.

The High Court yesterday granted Ms Kerins leave to bring judicial review proceedings against the PAC and others.

John Rogers, Senior Counsel for Ms Kerins, told the court that his client was seeking an injunction restraining the PAC from further pursuing matters in relation to her employment as Rehab CEO, or her work.

He said the PAC had displayed bias and had acted in an unfair and unlawful manner, straying outside its remit.