Quoted from  Music Business Journal:

"Mechanical and performing rights are under copyright in the Republic of Ireland for the lifetime of the songwriter plus an additional 70 year period.  This duration was extended from the traditional lifetime+50 year period by the Irish Government's statutory instrument no. 158 in 1995, and was in accordance with the European Community's (Terms of Protection of Copyright) Regulations."

See also:

Irish Music Rights Organisation
MCPS  This is the UK branch; MCPS Ireland is, I think, separate now, but doesn't seem to have a website of its own yet.