Ireland has made a joint claim with Britain, France and Spain over an 80,000 sq km area of the continental shelf over 200 miles off the south coast.
The bid is the first ever joint submission under the UN Law of the Sea Convention, and would, if successful, secure claims to oil and gas resources, as well as mineral and biological resources, on the seabed. The bid relates to territory in the Celtic Sea and Bay of Biscay, equivalent in size to the island of Ireland.
If successful it may be seen as "tremendously significant" in future years given soaring energy prices and improving capabilities to tap mineral resources in deeper waters, according to Minister for Foreign Affairs Dermot Ahern.
"We are effectively locking up control of thousands of square kilometres of unexplored seabed deep into the mid and south Atlantic for our children and their children," he said.
Under the UN Law of the Sea Convention, a coastal state can claim a continental shelf or sub-sea territory of 200 nautical miles, but must make a scientific case to the UN's Commission on the Limits of the Continental Shelf if seeking to extend beyond this.
The commission is chaired by Dr Peter Croker from the Department of Communications, Marine and Natural Resources.
Ireland has laid its claim to the 200-mile exclusive economic zone (EEZ) independently of the exclusive fishery limits which were ceded to the EU under the terms of the Common Fisheries Policy.
It is currently awaiting a decision on southwest limits. However, this island's sub-sea "footprint" could extend up to 500 miles in certain areas, such as off the northwest coast, and has been the subject of extensive mapping under the national seabed survey.
In October 2003, consultations were initiated between Ireland, Britain, France and Spain on unresolved boundaries to the south of this island, and it was agreed to make a joint submission to the UN before May 21st.
This will ensure that it is on the agenda for the UN commission's meeting in New York from August 21st to September 15th.
Following the commission's ruling, the four governments will then engage in negotiations to divide up the area, which could mean that Ireland's territory is enlarged by between 30 and 40 per cent.
The extended boundaries would have implications for the Naval Service, which is currently involved in consultations on its fleet-replacement programme.