The National Union of Journalists (NUJ) has described as a grave breach of trust "the secret nature of payments" made by RTÉ to presenter Ryan Tubridy.
In a statement issued after a meeting with RTÉ Trade Union Group officials, NUJ Irish Secretary Séamus Dooley said the "revelations have shocked and dismayed NUJ members and staff throughout the organisation".
"RTÉ, as a public service broadcaster, has built a strong reputation for trust, the cornerstone of any media organisation.
"The secret nature of the payments is a breach of trust unparalleled in the history of RTÉ. It is a betrayal of the workers and has long-term consequences for the relationship between RTÉ and its employees."
He said it must be remembered that when these payments were being negotiated, "RTÉ and the Trade Union Group were engaged in negotiations on pay for their members.
"The Trade Union Group commissioned an external financial consultant to carry out an independent analysis of the finances.
"It is now clear that while RTÉ offered to 'open the books', not all financial information was available to the consultant or the Trade Union Group," Mr Dooley said.
He added that the additional money paid to Ryan Tubridy is the equivalent of the salary of a journalist in RTÉ, where most staff "are on relatively modest salaries".
While the RTÉ Board acted with haste when the irregularities were highlighted, Mr Dooley said, he added "there are profound questions to be answered by the Executive Board, by the Director General and the Board itself in relation to corporate governance".
The NUJ is considering its position and formulating a more detailed response to the development, he added, but it "has long expressed serious reservations about commercial arrangements and the use of third parties to negotiate remuneration packages".
Meanwhile, the NUJ RTÉ sub-branch said that members who work at the broadcaster are shocked and infuriated by news of the payments which has "betrayed the trust of the Irish people but also the trust of its workforce".
In a statement it said: "These secret payments were being made as the company attempted to subject ordinary staff to pay cuts; subsequently limited pay increases by arguing that it could not afford a pay rise in line with inflation; and refused to honour claims for pension and holiday payments that dozens of RTÉ workers lost out on due to the company's use of bogus self-employment practices."
It said researchers on RTÉ's The Late Late Show "can work for as little as €32,700 annually" and the maximum salary for researchers on the programme is €55,600 - a level is only reached after a 12-year period.
The sub-branch has called an emergency meeting of members for tomorrow to discuss the implications of the revelations.
Immense damage to relationship with staff - Trade Union Group
The RTÉ Trade Union Group (TUG) has expressed shock and disappointment in relation to the payments to Mr Tubridy.
Speaking after a meeting of the officials of the group of unions, TUG Chair Stuart Masterson described the news as "a significant breach of trust with staff and their representatives, with Government and with the Irish Public".
He said RTÉ has "done immense damage to the relationship with staff" as the payments were made "when staff were engaged in cost-cutting negotiations with management".
Mr Masterson said the TUG expects "the investigation is conducted in a completely open and transparent manner" and "will be requesting a meeting with the Chair of the Board to get a better understanding of why
and how this happened".
Read more:
RTÉ admits paying Tubridy €345,000 more than declared
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Read: RTÉ's full statement on payments to Ryan Tubridy
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Martin to meet RTÉ chair
Minister for Arts and Media Catherine Martin said she will meet the chairperson of RTÉ on Monday, saying she is "extremely concerned at the details" revealed today.
The public, Ms Martin said, "rightly expect much higher standards of transparency and accountability from Ireland's public service broadcaster.
"It is unacceptable that these have not been met. It will be critical for the Board to identify whether there are wider governance issues that need to be examined and addressed, and to ensure that there is appropriate accountability for what has occurred.
"It will be equally important for the Board to demonstrate that it is putting in place appropriate structures and processes to prevent a recurrence of a matter of this nature," Ms Martin added.
PAC seeks explanation from RTÉ
The chair of the Public Accounts Committee has written to members requesting the committee seeks "an immediate explanation from RTÉ".
Sinn Féin TD Brian Stanley described what has happened as "utterly unacceptable and yet another serious breach of trust between our national broadcaster and the public".
In a statement, he added: "Just last year, RTÉ was forced to make a settlement of €1.2m to Revenue for unpaid employee PRSI and the broadcaster is now under investigation by the Department of Social Protection for the misclassification and bogus-self employment of over 100 employees.
"Today's revelations are just yet another example of the poor levels of transparency and questionable culture that has dominated RTÉ for too long, and this needs to change."
Social Democrats TD Catherine Murphy, who is vice-chair of the PAC, said: "Today's bombshell revelations involve a breach of trust from an organisation that has repeatedly put on the poor mouth about its dire financial situation when seeking an increase in the television licence fee.
"It should also be noted that these secret payments to one of its stars were made at a time when ordinary workers at RTÉ were being subjected to pay cuts, pay freezes and redundancies."
Ms Murphy said she is seeking to bring RTÉ and officials from Minister Martin's department before the PAC in the coming weeks.
