The former boss of RTE Dee Forbes sent a medical certificate to the Dail Public Accounts Committee (PAC) this week to say she is still unfit to testify before them.
The doctor's note was provided at her own behest by her solicitor.
The move came as PAC members considered taking legal action to force her to appear before them at a meeting they held behind closed doors last Tuesday.
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However, the members decided to postpone any High Court action to give the under-fire former Director General more time to recover and get back to full health.
It is understood the doctor's note did not specify what illness Miss Forbes is suffering from.
A PAC source said: "This is the first time Miss Forbes has sent us a medical certificate that she is unwell and not medically fit enough to appear before us. We have to accept her doctor's word that she is sick in good faith. Up until now they just sent us a letter saying she is ill.
"We have been trying to get her to come before our Committee since she left RTE and the Ryan Tubridy payments scandal broke last June.
"She has effectively been sick for over five months now and we do not know what is wrong with her. She has sent us a medical certificate and we have to respect that."
The PAC members are still determined to get Miss Forbes to come into the Dail and to explain to them what she did or did not know.
She was centrally involved in all the controversial negotiations involving Ryan Tubridy's contact, the secret payment of €225,000 guaranteed by RTE to him for additional work with The Late Late Show sponsors Renault, and the decision not to publicly publish his correct salary.
The PAC chairman Brian Stanley has already publicly said she has serious questions to answer and must at some stage come into Leinster House and give her side of the story.
One senior PAC member said: "Dee Forbes is one of the most important figures in this whole RTE saga. She was paid €300,000 a year as Director General and needs to come in and give us answers.
"We accept she is sick but at some stage she will have to testify. She can't keep putting off the inevitable. If she does not cooperate we will at some stage in the future have no choice but to go to court to force her to appear before us.
"The people of Ireland who paid her wages for several years deserve answers."
Miss Forbes is believed to be recuperating from her illness at her home in west Cork.
Earlier this week, her successor Kevin Bakhurst announced a radical overhaul of RTE including 400 redundancies.
The station has lost millions in TV licence fee revenue after a public backlash at the mismanagement within the public broadcaster.
It is believed several members of the Government want to keep the €160 licence fee but give it a new name and get the Revenue Commissioners to collect it. A final decision will be made in the New Year.
