Media Minister Catherine Martin has been warned about the "devastating impact" the Covid-19 pandemic has had on broadcasting.
A briefing prepared by Communications Department officials set out the stark effect cuts to the advertising market will have on the sector.
It comes after the revelation that 122 staff members at RTÉ earned more than €100,000 last year.
RTÉ was already in difficulty before the coronavirus crisis, recording a deficit before tax and exceptional items of €12.6m in 2018.
Department of Communications officials said its finances are "not sustainable and are undermining its capacity to remain relevant in an increasingly competitive and fragmented broadcasting sector while continuing to deliver on its statutory responsibilities as a public service broadcaster".
TG4, meanwhile, is faces a "very challenging financial environment as a result of Covid-19".
The briefing for Ms Martin said the Irish language broadcaster has suspended all non-essential programme-making while ensuring that essential programmes such as Nuacht TG4 and Cúla4 ar Scoil "are produced in a safe manner".
The briefing says although licence fee revenues have risen by €10m since 2014, this has not prevented the emergence of a growing deficit at RTÉ.
It says RTÉ's Annual Report and Group Financial Statements for last year are not yet finalised.
The officials set out draft figures for last year and an income statement outlook for this year, but the data is redacted in the documents published last night.
Priorities for this year in relation to the broadcaster is said to be engagement in relation to RTÉ's financial position and the implementation of a revised strategy for 2020 to 2024.
TG4 is implementing a series of measures worth at least €3m, aimed at trying to sustain the independent screen economy.
The officials say: "These include new development rounds for television programmes and feature films , the re-acquisition of rights and the commissioning of long-form and short-form content which can be produced safely."
RTÉ said last night that in its revised strategy published last year "income was no longer sufficient to deliver against remit, or fulfil RTÉ's national role as originally intended".
It said the financial challenges were "a serious threat to the future of public media".
A statement said RTÉ "remains in discussions with the Government regarding both our short-term financial challenges and longer-term reforms to fix the broken TV licence funding system".
It has complained that more than €50m a year is lost through TV licence evasion and avoidance.
The statement also said: "While there has been a steady industry demand for advertising on RTÉ in August, following a number of challenging months, the situation remains uncertain."
Separately, 122 RTÉ staff members earned more than €100,000 last year. Of these, 24 earned between €150,000 and €250,000.
The figures do not include top earners such as Ryan Tubridy as they are independent contractors.
Against the background of mounting losses, numbers employed at RTÉ increased last year from 1,822 to 1,831.
"As with any large organisation, small variations in headcount can occur, resulting from the timing of recruitments," a spokesperson said.