An Bord Pleanála has ruled that fencing across a disputed right of way on Fenit Island is not exempted development.
The matter was referred to the board by campaign group, Keep Ireland Open who claimed that fencing was obstructing historic paths along the shoreline.
The erection of the fencing has been the subject of a number of protests by locals and walkers in recent years.
Inspector with the Bord, Philip Davis concluded that the fencing works are not exempt under planning regulations.
Cllr Toiréasa Ferris said the decision was a boost for those who have been campaigning to save the right of way on the island and for ensuring access to Fenit Castle.