An emergency meeting of members of the National Union of Journalists (NUJ) working for RTÉ will be held today.
It comes after the broadcaster admitted to undeclared payments to Ryan Tubridy between 2017 and 2022.
The payments totalled €345,000, and have been described as a serious breach of trust.
RTÉ has confirmed the former Late Late Show host will not present his radio show today.
Seamus Dooley from the National Union of Journalists said it will be tough for RTÉ to start re-building trust.
Mr Dooley told Newstalk: "The agreement to pay additional sums to Ryan Tubridy occurred at a time when RTÉ was pleading poverty, when it was seeking pay cuts, when RTÉ was enforcing austerity measures.
"And all the time this was going on in the background, that's a significant breach of trust, and that undermines the trust that is at the heart of industrial relations... and trust is hard won and easily lost so there's a lot of work for RTÉ to be done at this stage."
Mr Tubridy has said he was surprised to learn of errors by RTÉ regrading his remuneration and issues surrounding separate payments made to him under a commercial deal.
Regarding the latter, the presenter received €150,000 from RTÉ in 2022, in addition to his reported annual remuneration.
The matter was the subject of an independent review carried out by Grant Thornton after the issue was raised in March, the findings of which have since been received by RTÉ's board and the audit and risk committee.
In a statement issued on Thursday afternoon, RTÉ confirmed the payments which prompted the investigation were separate from Mr Tubridy's annual remunerations, and were instead part of a deal in which the State broadcaster guaranteed the presenter an additional annual income of €75,000, "which was intended to come from a commercial partner".
