Social Democrats TD Cian O'Callaghan has asked if an inquiry into an alleged conflict of interest at An Bord Pleanála, recently ordered by Minister for Housing Darragh O'Brien, will be expanded to take account of new allegations.

The deputy chairman of the board, Paul Hyde, denies any allegations of a conflict of interest.

He has agreed to absent himself temporarily from his duties until the matter has been investigated.

In the Dáil today, Mr O'Callaghan said the terms of reference of the investigation, currently being undertaken by senior counsel Remy Farrell, does include some discretion as to what can be examined but he said this "appears to be quite limited".

He asked Tánaiste Leo Varadkar: "Given the centrality of An Bord Pleanála to the planning process, and the absolute necessity that it retains the confidence of the public, can you confirm that the terms of reference of Mr Farrell's report are now going to be expanded to include these further allegations concerning Mr Hyde?"

Mr O'Callaghan also asked: "Is any investigation being conducted, or contemplated, into allegations that another member of the board breached An Bord Pleanála's code of conduct?"

In reply, Mr Varadkar said these were "very serious allegations and need to be taken seriously and properly investigated".

However, he said people were entitled to due process and he noted Mr Hyde's denial of the allegations.

Mr Varadkar said Mr O'Callaghan’s questions were "very specific" and accordingly he would "ask Minister O'Brien to come back to you with specific answers to your questions, because I don't want to give you an answer here which might be incorrect".

He added: "I guess in relation to the scope of the investigation, and whether it should be widened or not, that's a matter for Minister O'Brien to consider.

"Obviously, he will need to see ... whether any additional allegations have substance and, on foot of that, he will need to make a decision as to whether the terms of reference need to be changed or whether the investigation needs to be widened.

"That's really a matter for Minister O'Brien to consider."

Solidarity-PBP TD Paul Murphy told the Dáil that he expects "new revelations will emerge in the next days about the conduct of another member of the board of An Bord Pleanála".

He asked if the terms of reference of the inquiry should be broadened.

Mr Varadkar responded that is a matter for Minister O'Brien "as to whether he thinks it is appropriate or not to expand the scope of the existing investigation, or to find another way to have them examined".