As I have indicated in response to a number of similar questions in the past Ireland is not party to the Schengen Implementation Convention and has no plans at present to become a party or to seek observer status. There is no formal status less than full accession to the convention and observer status is accorded by the status party to the convention only as a preliminary step to a rapid accession.
My Department arranged last December to be briefed about developments on a regular basis by the State holding the Presidency of the Schengen states. The question of Ireland seeking to join the Schengen arrangements has been reviewed from time to time; the conclusion so far, being that it is not in Ireland's overall interest to do so.