Members of the RTÉ Executive and the RTÉ Board have appeared before the Dáil Public Accounts Committee (PAC) in the wake of the payments controversy at the broadcaster.
Director General Kevin Bakhurst said that the broadcaster "should not be brokering or facilitating commercial arrangements with its contractors" as "the level of fees in contracts of this nature are too high".
In his opening statement, Mr Bakhurst said the non-disclosure of payments has created "one of the most shameful and damaging episodes in the organisation's history".
"The public were misled, as were you as public representatives. That is completely unacceptable. I want to assure you that lessons have been learned, and actions are being taken."
Mr Bakhurst added that the contractual arrangements for presenter Ryan Tubridy, the public misstatements of his remuneration, and other subsequent discoveries "remains a source of frustration to the public, to the RTÉ Board, to the elected representatives who have engaged on this issue, and to staff within RTÉ".
The broadcaster "should have operated with greater transparency, and should have applied much higher standards of honesty and integrity in terms of its public statements", he told TDs.
Mr Bakhurst said he has instructed all divisions in RTÉ "to give the fullest co-operation possible with these investigations, and with committee queries".
"I am absolutely determined to implement the change and reform which will help us draw a line under this shameful period in RTÉ's history and to rebuilding trust in public service broadcasting."
Mr Bakhurst led a delegation that included Acting Deputy Director General Adrian Lynch, Director of Legal Paula Mullooly, Group Head of Sport Declan McBennett, Chief Financial Officer Richard Collins and Head of Strategy and Commercial Compliance Conor Mullen.
Staff representative on the board Robert Shortt was also in attendance, while former director general Noel Curran was due to participate by video link.
Former board chair Moya Doherty said that, regrettably, she was unavailable to attend.
Former chief financial officer Breda O'Keeffe told the PAC she was also not available, but maintained she had nothing further to add to a previous statement.

RTÉ Board Chair Siún Ní Raghallaigh told the committee that the new director general is "in a few short days steadying the ship of RTÉ by taking swift action on a range of important matters, from leadership reform to the introduction of a register and more".
She said she particularly welcomed his commitment to ongoing staff engagement.
Ms Ní Raghallaigh said Mr Bakhurst was "facing up to the issues of the past and the lamentable failures that have emerged".
She said: "As Chair I am committed to being as open and transparent as possible and to placing facts in the public domain at the earliest opportunity. That is what I am doing here today."
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Tripartite deal 'central' to negotiations around Ryan Tubridy's wider contract with RTÉ - Lynch
RTÉ's Interim Deputy Director General Adrian Lynch said the misstatement of the fees paid by RTÉ to presenter Ryan Tubridy has precipitated the "single biggest crisis" in the history of the broadcaster.
In his opening statement to the PAC, he said that RTÉ takes full responsibility for these misstatements, and the events that led to them.
Mr Lynch said the tripartite agreement between RTÉ, Renault and Ryan Tubridy was "central" to negotiations around the presenter's wider contract with the broadcaster.

The Interim Deputy Director General also challenged a claim by Ryan Tubridy's agent, Noel Kelly, that he did not know that Renault had not renewed years two and three of the commercial deal.
"In relation to some of the commentary made here on Tuesday last, RTÉ must clarify the proposal to underwrite these payments was central to the contractual negotiations between RTÉ and Mr Tubridy," he said.
"We believe that the substantive contract would not have been signed without the additional commercial agreements or the underwriting.
"Moreover, we contend that the payments of €75,000 per year for year two and three of the commercial contract were pursued by NK Management (Mr Kelly's company) despite it knowing that the Renault contract was no longer in place."
Lynch clarifies 'key point' in relation to Tubridy payments
Interim Deputy Director General Adrian Lynch said he had "something quite material to add" in relation to payments to Ryan Tubridy and wanted to clarify "one key point".
It related to testimony of "a verbal agreement on 7 May between [agent] Noel Kelly and [former Director General] Dee Forbes".
Mr Lynch noted that Mr Kelly said he never met Ms Forbes without legal and finance teams in attendance.
But Mr Lynch said he has found a record of a Teams call on Monday 25 April 2022 where the sole attendees were Noel Kelly and Dee Forbes.
He added that "there was no Renault deal after the first year. There were no other six events".
"In that situation, Mr Kelly then sent to Ms Forbes on April 25 an email to say: "Hi Dee. I hope you are well. It was good to catch up today. If you could please get Ger, Geraldine O'Leary, to send me on the invoicing details".
Payments were 'appalling' and 'disgusting' - RTÉ Director General
Labour TD Alan Kelly asked if Ryan Tubridy's claim that he had taken a 20% pay cut was accurate.
"He took a significant pay cut," replied RTÉ Director General Kevin Bakhurst.
"That's undoubtedly true. I wouldn't want to say yes on 20% because I haven't got my calculator."
Mr Kelly also asked if Mr Bakhurst thought that making the two €75,000 payments through a barter account was "appropriate".
"When I heard about those payments I found it appalling, disgusting," replied Mr Bakhurst.
"I've no idea why anyone involved ever thought that was appropriate, on any side, and there was more than one side to it."
RTÉ apologises to Renault
RTÉ's acting deputy Director General apologised to Renault over the fallout from a commercial agreement involving the car manufacturer, the national broadcaster and presenter Ryan Tubridy.
Responding to Sinn Féin TD John Brady, Adrian Lynch said: "I want to apologise to Renault because Renault have been dragged into this, so it's outrageous, in a way."
He said it is "completely obvious" that the payment of €75,000 from Renault for three events with Mr Tubridy was from a one-year agreement.
RTÉ had agreed to underwrite two further payments of €75,000 in the event a commercial partner could not be found for subsequent years.

Mr Tubridy, who received a further €150,000 on that basis, has previously said he would pay it back if those events do not proceed.
Asked if RTÉ had asked Mr Tubridy to return the money, Mr Lynch said the broadcaster had not because there was a verbal agreement given to his agent that it would pay the money.
New Director General Kevin Bakhurst said: "There's two things here for me: there's a legal agreement and RTÉ has a liability.
"Then, I think there's a moral question about what's the right thing to do and I think when we do come to have any discussions with Mr Tubridy going forward - I welcomed his offer the other day and we'll wait and see what he does about it."
Meanwhile, an interim report from accountants Grant Thornton has concluded that the remuneration figures for RTÉ's ten highest paid on-air presenters was correctly stated publicly, and properly accounted for by RTÉ, during the period 2008 to 2022 inclusive.
The review was commissioned by the RTÉ Board, after a previous Grant Thornton report had uncovered the non-disclosure of payments to Ryan Tubridy's agent Noel Kelly via RTÉ's barter account.
In this second report, albeit an interim one, the accountancy firm concludes that RTÉ had correctly stated the figures over the 15-year period, with the exception of what had been identified in the first report.
The interim report was furnished to the Audit and Risk Committee of the RTÉ Board yesterday. Its findings have been shared with members of the Public Accounts Committee.
The second Grant Thornton interim report states that work is ongoing regarding the 2008-2009 period, given the historical nature of those records.
The report finds "one minor exception" when payments to RTÉ's ten most highly paid presenters were not correctly recorded by RTÉ.
The amount overstated is €1,359 and the report says this is related to unpaid annual leave of one presenter.
The report states: "The difference of €1,359 is not significant, particularly relative to the total published remuneration figures of the Top Ten Earners, and has no impact on the rankings of the Top Ten Earners."
Forensic accountants from Mazars were due to meet officials from the Department of Tourism, Culture, Arts, Gaeltacht, Sport and Media this morning about a review of RTÉ's books.
It is understood there is a desire to get the process under way as quickly as possible.
The review was announced by Minister Catherine Martin last week, with the appointment of Mazars disclosed yesterday.