Businessman Denis O'Brien has received permission to buy Today FM and Highland Radio but has been blocked in his bid to add FM104 to his expanding portfolio of radio stations.
The Broadcasting Commission of Ireland (BCI) decided the purchase of FM104 could give Mr O'Brien's Communicorp an overly dominant position in the Dublin market.
Communicorp already has shares in 98 FM and Spin 103.8 FM which operates in Dublin and has obtained a licence to operate a regional station in the southwest. Mr O'Brien would have acquired three of the five commercial franchises in the capital if he obtained permission to buy FM104.
The BCI however granted permission for the purchase of Today FM, the State's largest independent national broadcaster despite Mr O'Brien's interest in Newstalk, the only other national independent broadcaster.
It also gave the go-ahead for the purchase of Highland Radio which operates the only current north Donegal licence and has larger share of its market than any other local operator.
In a short statement this evening, the BCI said in accordance with legislation, it considered "the desirability of allowing any person, or group of persons, to have control of, or substantial interests in, an undue amount of communications media in a specified area."
Mr O'Brien who has also interests in media and communications companies throughout the world has recently built up a significant stake in Independent News and Media, which owns the Irish Independent, Sunday Independentand several titles in a number of southern hemisphere countries.
Communicorp, which operates 38 radio stations in seven European countries, had offered UK media firm, Emap, around €200m for the purchase of the three stations.
It must await the decision of the Competition Authority which is also considering the consolidation of so much media interests in one firm. It is due to give a decision at the end of the month.
The National Union of Journalists (NUJ) this evening called on Mr O'Brien to confirm that Communicorp would recognise existing collective agreements and recognise the right of employees to trade union representation.
"In the past Mr O'Brien has not recognised trade unions," Seamus Dooley, NUJ Irish Secretary said in a statement.
"The NUJ is also asking that ministerial approval for the acquisition of the two stations should be dependant on commitments in relation to trade union recognition and employment standards," he said.
The NUJ also wants to see the establishment of a commission to examine all aspects of media ownership in Ireland.
"What we need is a Commission which would examine all aspects of media policy - including ownership; employment standards and training - in a coherent manner, recognising the inter-connection between publishing and broadcasting at regional and national level," Mr Dooley said.