Conservationists had being trying to block the plans since 2014
Clare County Council has granted planning permission for development at US President Donald Trump's resort in Co Clare.
The planning relates to "coastal erosion management works" at and near the Trump International Golf Links and Hotel.
However, the decision could still face an appeal to An Bord Pleanála within four weeks.
The development includes two new structures at Carrowmore Dunes adjacent to the hotel, which its claims are necessary to safeguard the resort's golf links from storm damage.
In its ruling, the county council says: "The development includes the provision of two new protection structures at the dunes.
"The construction/development will include excavation of existing sand, the use of sheet piling backstops with soil nailing, goetextile underlay, armourstone protection to the sheet piles with sand and cobbles currently on the beach".
The works will be over a distance of 256 metres at the northern end of Doughmore Bay, west of the golf course.
The permission is subject to nine conditions, one of which is to "mitigate the potential impacts if the development on the environment, to protect European sites".
Ecologists are also to be appointed to oversee the construction of the project.
Conservationists had attempted to block the plans since 2014.
The dunes are a Special Area of Conservation and a Natura 2000 site, home to reefs.
Storms in 2014 wore away sand dunes in Doonbeg by several metres in some places.
An Taisce, which works to preserve and protect Ireland's natural heritage, says it "regrets" the grant of planning permission.
It says: "An Taisce will not be making a decision as to whether it will appeal to An Bord Pleanála until it has had a chance to study the details of the grant."
But it says it is also seeking information from Heritage Minister Josepha Madigan "to determine what action the National Parks and Wildlife Service (NPWS) is taking in response to the decision."
An Taisce says the NPWS had made a highly critical submission on the proposal on scientific grounds, so that information is being sought as to whether an appeal by the NPWS to An Bord Pleanala is now being proposed.
"In view of the ecological damage which has occurred at the Trump family golf course at Menie in Scotland, An Taisce is also seeking intervention by Minister for Culture Heritage and Gaeltacht Josepha Madigan to investigate the site and take action ensure that the nature conservation conditions attached to the 1999 planning permission for the golf course development are being complied with", An Taisce adds.