Gardaí seized a suspected sub-machine gun along with a silencer, loaded magazine, and ammunition during the course of a search in the Dublin 11 area.
"As a result of information received, gardaí from Finglas conducted a search of a maintenance area at an apartment complex in Finglas at approximately 1.10pm on Friday, November 25," said a Garda spokesperson.
"During the course of this search, a suspected sub-machine gun which had been wrapped in white plastic wrapping and then double bagged in black bin bags, was located and seized.
"Beside the suspected firearm was a silencer, loaded magazine and a small white bag containing ten 9mm bullets, all of which were seized."
All of the items seized will be sent to the Garda Ballistics Unit for analysis, it was added.
Investigations are ongoing.