Under the change, transactions, where companies with no prior media interests buy Irish media businesses, are no longer counted as media mergers. In such mergers, the Minister for Enterprise has special legal powers, which are designed to protect media diversity, including the power to block acquisitions.

A spokesman for the Competition Authority also admitted that the changes could also potentially allow media groups to set up special vehicles to purchase their rivals without ministerial scrutiny.

He said, however, that this issue was "beyond the scope of the authority under current legislation" but such activities may be identified as a conflict of interest under the authority's procedures for investigating normal mergers.

He said that the changes to the law had been suggested by the Competition Authority in an attempt to reduce the number of media mergers it handles. He said that the previous definition of media merger was so broad that many of the transactions involved had no relevance to Ireland.

However, the Irish Secretary of the National Union of Journalists (NUJ), Seamus Dooley, criticised the changes. "I'm alarmed that the Competition Authority neglected to appreciate the significance of its intervention, " he said. "The NUJ is already concerned about dominance in the print and local radio sectors."

But Dorit McCann, a senior associate in A&L Goodbody's competition law unit, said that the changes would free up Competition Authority resources and would make it easier for multinationals and private equity firms to buy Irish media assets.

She said, however, that the legal definition of a media merger was still too strict. "The threshold has been raised but it arguably doesn't go far enough. You could still have a situation, for example, where a private equity house has an interest in a station in Ecuador and then buys an Irish station and the merger has to be notified to the Irish Competition Authority."

Under Irish law, the Competition Authority has a two-stage review procedure for mergers.

Simple deals are usually cleared after a phase one review, which takes about a month. More complicated deals, however, usually undergo a second, more detailed, review, which can last more than four months.

In media mergers, the Minister for Enterprise can order the authority to start a phase two probe even if the authority disagrees with him and, at the end of the process, he can block an acquisition, even if the authority has cleared it.