The Oireachtas Committee on Media has received legal clearance to invite a number of former RTÉ executives and board members to its session next Wednesday.
The three individuals are former Director General Noel Curran, former Chief Financial Officer Breda O'Keeffe and former Chair of the RTÉ Board Moya Doherty.
The invites were issued this afternoon.
Earlier, committee Chair Niamh Smyth said presenter Ryan Tubridy and his agent Noel Kelly will not be invited for now, as it was felt by members that there was still a "distance to go" with RTÉ management and board members.
Ms Smyth said that she wanted to see the executive remain in place, so that the committee could ensure that certain personnel remained available for questioning.
There was strong criticism of the decision of RTÉ Chair Siún Ní Raghallaigh to accept the resignation of former Director General Dee Forbes.
"We're not looking for heads at this time. We're looking for truth and honesty," Ms Smyth said.
RTÉ has been given a deadline of Tuesday to furnish all information and documents requested by committee members at their last session.
The RTÉ Board is a body made up of 12 people that makes policy for the broadcaster, while the Executive Board is a committee composed of senior management responsible for its day-to-day running.
Meanwhile, Minister for Media Catherine Martin has requested to meet with the Chair of the RTÉ Board Suin Ni Raghallaigh, along with the incoming Director General Kevin Bakhurst, in the coming days.
It is understood that during this meeting they will discuss a range of matters, including the external review of corporate governance and culture in RTÉ, Mr Bakhurst's plans to reconstitute the executive board and engagement with RTÉ staff.
They are also likely to discuss the Grant Thornton Review of payments to Mr Tubridy between 2017 and 2019.
He said: "I don't think we can rule out the fact that it's not just a case of irregular payments, that some of these payments may have been on the wrong side of the law. But I don't want to jump to that conclusion."
The Taoiseach said it was not unusual for a corporation to entertain clients.
However, he said: "The fact that it was so untransparent, even concealed, that payments were made for work that perhaps wasn't done. That's much more serious, I think, and is a matter of real concern."
Meanwhile, Center Parcs has confirmed they did not wish to renew their sponsorship of The Ryan Tubridy Show.
The current sponsorship has been paused since Friday 23 June and the current sponsorship contract will expire on 28 August.
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Elsewhere, Minister Martin said that she is in the "final stages" of drafting the terms of reference for an external review of RTÉ.
The document is unlikely to be finalised today. It is possible that the matter will be discussed by the Cabinet again on Tuesday, with the review getting under way soon after.
Members of the Public Accounts Committee have been highly critical of yesterday's performance of senior RTÉ Executives and the RTÉ Board, who sought to explain how and why non-disclosed payments were made to Ryan Tubridy as well as other corporate governance failings.
Fianna Fáil's James O'Connor said: "It was a catastrophic failure by the Executive Board of RTÉ and I think the Financial Controller should immediately step aside."
Labour Deputy Alan Kelly said: "In my many years on PAC, this was the worst performance I've seen.
"This is an executive that isn't functioning and can't continue. Neither can the board after what we saw."
Sinn Féin Deputy Imelda Munster: "They [RTÉ Executive] misled the public, workers, and the Oireachtas every step of the way. That privileged insider culture needs to be completely rooted out."
Fine Gael's Alan Dillon said: "The wounds revealed in the proceedings will resonate deeply for the foreseeable future until RTÉ's executive management take accountability to reform a culture associated with fraudulent invoices, off balance sheet accountancy and secret payments."
Yesterday, Ms Ní Raghallaigh told the committee that she was appalled by how payments were recorded and presented in the company's accounts and that it appeared it was an act designed to deceive.
The committee was told that the RTÉ Executive Board would be reconstituted and a register of interests for senior editorial staff and others would be drawn up.
The person in the cross hairs was RTÉ's Chief Financial Officer Richard Collins, as he was forensically questioned about a €75,000 invoice labelled as "consultancy fees", which was a concern by auditors Deloitte.
He said he went to RTÉ Director General Dee Forbes who told him, he said, it was "for advice she'd received around how RTÉ structured itself during Covid-19".
Sinn Féin's Imelda Munster and Fine Gael's Colm Burke took him to task for a failure, in their eyes, as to why he did not question it, follow-up on it, or get to the bottom of it.
Mr Burke said the vehicle used, the barter account, was a slush fund. He was incredulous that the commission per transaction was 35%.
Mr Collins said he was given "comfort" by the fact that it was signed off by Ms Forbes.
He also said more than €1 million went through the account over a decade.
The committee heard RTÉ used it to pay €275,000 for tickets and travel for clients for the Rugby World Cup, IRFU tickets and the Champions League Final.
Ms Ní Raghallaigh said this was "outrageous".
Additional reporting Paul Cunningham, Micheál Lehane
