Former RTÉ director general Dee Forbes will not attend the Oireachtas Media Committee hearings on the payments controversy at the national broadcaster.
A spokesperson confirmed that it is due to health reasons.
It comes as the Media Minister says details of an independent review into the culture and management at RTÉ will be ready by the end of the week.
A two or three person team will also examine the relationship between management and staff in the wake of revelations about hidden payments to Ryan Tubridy.
Cabinet discussed the proposals this morning and expects the work to be completed in a matter of months.
In a statement, Catherine Martin said she had briefed government colleagues about the external review she ordered.
She said: “As I have said before, the revelations from RTÉ this past week are unacceptable and damaging to both RTÉ and to public service broadcasting in general.”
The minister continued: “Trust and confidence have been broken and it is essential that RTÉ puts the full facts on public record as a matter of urgency, to avoid further damaging public trust.”
She said she had written to the RTÉ chairperson Siún Ní Raghallaigh to set out key questions that must be answered.
Ms Martin said: “In particular, the public wants to know who signed off on the payments, who else was involved or aware of these transactions, and when will the further Grant Thornton report commissioned by RTÉ which relates to the understatement of the renumeration of RTÉ’s top paid presenter by €120,000 between 2017 and 2019 be completed.
“At times of crisis, it is the failure to put all information on the record at the earliest possible juncture that does most damage.”
Meanwhile, more than one hundred members of staff at national broadcaster RTÉ have staged a protest at its Dublin headquarters, following a scandal involving undisclosed payments to its highest-paid star Ryan Tubridy.
Staff represented by the National Union of Journalists and the Services Industrial Professional and Technical Union gathered on a plaza in the Donnybrook campus of RTÉ to voice their concern over pay, conditions and governance in the wake of the revelations.
Chair of the RTÉ Trade Union Group, Stuart Masterson, said anyone who had involvement in the undisclosed payments had to appear before the Oireachtas committees.
“A company’s culture is led from the top,” he said.
