A fresh warning has been issued to RTÉ staff following a recent spate of successful account hackings which follows similar events in recent months.
The hacking comes over a year after the national broadcaster said it had beefed up its email security system following a previous hacking attempt.
On that occasion, an impostor sent a series of emails to a small number of staff claiming to be from a financial institution.
Staff were told earlier this month in an email that an RTÉ staff member's computer account was compromised when they filled out a form in response to a phishing email requesting their username and password.
As a result, a large number of emails were then sent from this account requesting others to enter their username and password into a web-based form.
The email stressed that this was not an RTÉ Technology request.
A spokesperson for RTÉ was unavailable for comment.
However on the last hacking incident in March 2014, a spokesperson said that "like all organisations" RTÉ receives a large volume of spam email, almost 150,000 per day.
The spokesperson said they "continue to review their IT environment to minimise risks."