The Defence Organisation provides a broad range of marine security services; it also undertakes a diverse range of non-security related tasks in Irish waters and beyond. The Sea-Fisheries Protection Authority (SFPA) as competent Authority has a Service Level Agreement with the Department of Defence (DoD) to secure efficient enforcement of sea-fisheries law through support from the Irish Defence Forces. The Naval Service is the State's principal seagoing agency, with a general responsibility to meet contingent and actual maritime defence requirements. In support of the Navy, the Air Corps’ Maritime Patrol Aircraft are primarily tasked on domestic fishery protection missions.

Any proposal that has the potential to interfere with the performance by the Defence Forces of their security and non-security related tasks must be subject to consultation with the Defence Organisation. This includes potential interference with: Safety of navigation and access to naval facilities; Firing, test or exercise areas; Communication, and surveillance systems; and Fishery protection functions. Additionally, Haulbowline Naval Base in Cork is of strategic importance and there may be a need for future expansion of the Naval Base. Any future development proposals in Cork Harbour will also need to take cognisance of the requirements of the Naval Service.