Is the Irish government too cowed to do anything about the country’s largest media tycoon enlarging his empire?

Denis O’Brien, reputedly Ireland’s richest man, is the largest shareholder in the country’s largest newspaper publisher, Independent News & Media (INM).

That company has now agreed a deal to add seven more newspaper titles to its stable by acquiring the Celtic Media Group (CMG).

They include the Anglo-Celt in Cavan, the Meath Chronicle and the Connaught Telegraph in Mayo. In all, it extends INM’s footprint to five more counties.

INM is already the major player at national level. It publishes Ireland’s two largest-selling titles, the Irish Independent and Sunday Independent, plus the Sunday World and the Dublin Herald. It also has 50% of the Irish Daily Star.

O’Brien’s other media company, Communicorp, owns Ireland’s two leading commercial radio talk stations: Newstalk and Today FM. In addition, it owns Dublin’s 98FM, SPIN 1038, TXFM and SPIN South West.

And he has plenty of non-media holdings too, including a Dublin hospital, a prestigious Galway hotel and Siteserv, which provides services to the Irish state including the (controversial) installation of water meters. And he has many business interests elsewhere in the world.

In such circumstances, it is fair to ask whether the Irish government should simply nod through a further expansion of O’Brien’s media assets. Diversity and plurality are surely threatened.

The National Union of Journalists, which called in April this year for a commission to investigate media ownership in Ireland, has rightly registered its alarm at INM’s Celtic Media deal.

In its first statement on the matter, the NUJ said it was “gravely concerned” about the acquisition. In a follow-up statement, the union called for a full investigation into the impact on employment, competition and media diversity.

It urged Ireland’s communications minister, Denis Naughten, to use his powers in order to examine the deal, which is subject to approval by his department and by the competition commission.

As the NUJ pointed out, the announcement of the deal, for an undisclosed sum, coincided with a decision by INM to outsource editorial functions to the UK, with a loss of up to 27 permanent and contract jobs.

Celtic Media staff – numbering around 100 – will doubtless be concerned about the potential for future staff cutbacks at their papers too.

The publisher is owned and managed by a team that acquired the group in 2012 through a management buyout for a reported €5.5m. It is headed by a former Irish Independent business editor, Frank Mulrennan, and it is understood that he will rejoin INM.

Robert Pitt, INM’s chief executive, said: “We are very pleased that Celtic Media Group’s publishing titles are becoming part of INM’s portfolio of regional and digital titles.

“There are clear synergies arising from this transaction, which fit well with INM’s strategy to remain as a key player in the delivery of printed news content on a national and regional basis.”

He has previously said consolidation was needed in the national print sector in order to secure the viability of newspapers that face falling print circulation and a challenging advertising environment.

But the question for Minister Naughten is whether it is appropriate for INM, already the largest newspaper publisher on the island of Ireland (it has the Belfast Telegraph in the north), to grow larger still.