RTE has confirmed it was 65.2 million euro in the red last year following a major restructuring of the company.
As the state broadcaster insisted it is on target to break even in 2013, Communications Minister Pat Rabbitte warned he would keep a close eye on its finances.
A statement from the minister's department said he had made it clear RTE must return to stability this year.
"He considers that RTE will continue to operate in a challenging financial environment, particularly in the increasingly fragmented and competitive advertising market," it said.
"He is concerned by the continuing decline in commercial revenue and his department is closely monitoring the financial position of RTE on an on-going basis."
The net deficit emerged in the broadcaster's annual report for 2012, which also revealed an operating profit of 2.2 million euro.