Minister for Marine Noel Dempsey has expressed "delight" at a United Nations commission ruling which extends Ireland's continental shelf area beyond 200 nautical miles.
Minister for Foreign Affairs Dermot Ahern played a pivotal role in staking the claim to an additional 56,000sq km of territorial waters - said to match some 80 per cent of the State's land area.
Mr Ahern was informed earlier this month that the UN Commission on the Limits of the Continental Shelf had sanctioned the claim. The ruling will have particular relevance in relation to oil and gas exploration and environmental responsibilities.
Under the Law of the Sea Convention, a coastal state exercises sovereign rights over its continental shelf to explore and exploit the natural resources of the seabed and subsurface.
Ireland's sovereignty over fishing rights was ceded to the European Union after accession to the community.
Mr Ahern said that he was "very proud that Ireland had become one of the first countries in the world" to secure international recognition of its right to extend its continental shelf in this way.
The Russian Federation and Brazil have also received similar approval.
Mr Dempsey said that Ireland could establish the limits of the continental shelf. These limits, based on the UN commission recommendations, were "final and binding", he said.
Ireland still has two further claims in with the UN in relation to marine territory.
It has made a joint submission with France, Spain and Britain for an area in the Bay of Biscay, and a ruling on this is expected later this year.