RTÉ director general Dee Forbes has warned of "painful choices" ahead of a voluntary redundancy plan, which aims to reduce staff numbers by 250.
The station has announced more detail on structural and operational changes as part of an ongoing review at Montrose.
At a 90-minute meeting between the executive and staff, Ms Forbes detailed plans to reduce the size of the workforce. She admitted some tough decisions would have to be made.
"There's no disguising that alongside what I believe is an exciting future, there will also be some painful choices.
"Our financial situation requires us to reduce costs and employee numbers. We need to become a smaller, more efficient organisation. That will mean that we will lose some colleagues.
"It will also affect the scope of what we are able to do. Critically, we must ensure that we are investing in the programmes, reporting and content valued by our audiences."
Ms Forbes believed the cuts would ultimately benefit the station.
"The changes announced are important and necessary to ensure we can serve our audiences ... sitting still is not an option," she said.
But with full details of the voluntary exit programme and early-retirement scheme not being shared with staff until next week, many are still unsure of what will happen.
"To be honest, none of the staff or presenters really know anything yet," said one source.
An RTÉ spokesperson said the station was confident that enough members of staff would take voluntary redundancy or early retirement, and it would not have to consider compulsory redundancies.
"We expect to get the required number of people to take up the voluntary exit programme and the early retirement scheme and we are working on that basis," the spokesperson added.
It is expected staff with at least 10 years' service will be offered four weeks' pay per year, as well as the statutory entitlement of two weeks' pay per year, capped at two years' salary. Staff with less than 10 years' service are expected to be offered two weeks' pay per year of service as well as statutory redundancy pay.