Joe O'Toole has come under fire after saying the job of the expert group was to find 'enough sugar to make the medicine go down'.
He says he will remain impartial and listen to all interested parties in the course of the group's work.
Fianna Fáil TD Thomas Byrne says all parties need to be satisfied the commission is chaired properly.
While TD Catherine Murphy of the Social Democrats says the group's work will not be tenable with O'Toole in charge.
