RTÉ's plan to broadcast on the Sky digital network has been temporarily blocked by the Broadcasting Commission of Ireland (BCI).
The Commission has decided that the national broadcaster must first seek a licence, despite RTÉ's protestations to the contrary.
RTÉ had planned to begin broadcasting the television signals on Sky to homes in the Republic from April, while its radio stations would be carried on the full Sky network.
However, the Broadcasting Commission has ruled that Section 38 of the Broadcasting Act means that the rebroadcasting of any signals of Irish television companies must be first licensed by it.
Meanwhile, the Commission is expected to propose significant changes to the licensing regime governing the State's local radio stations, which come up for renewal next year.
The decision could mean that a number of licences in Munster, Leinster and the North-West could be consolidated to reflect population movements, and profitability records. RTE's director general, Mr Bob Collins told an Oireachtas committee on Monday that the station had secured a place on the Sky network for no charge.
The negotiations are regarded as a triumph within RTÉ, since ITV and the BBC pays Sky nearly £18 million sterling for the same privileges in the United Kingdom. However, the addition of RTÉ to its network is also a major plus for Sky, which is trying to boost its audience numbers in the Republic in advance of the arrival of other digital television services. RTÉ believes it could win an extra 140,000 thousand viewers in Northern Ireland and attract back an unknown number in the Republic though Sky.
In a letter to the Broadcasting Commission in December, Mr Collins insisted that his legal advice was that RTÉ did not require the approval of the Broadcasting Commission. The development was opposed by TV3 and by the Republic's cable companies, which are already forced to carry RTÉ's stations on its services for no fees.
RTÉ received planning permission early this month for a satellite dish to link up with the Rupert Murdoch-controlled television company.