Speaking in the Dáil, Minister for State Kevin Boxer Moran said the proposal of a tidal barrier put forward by groups such as Save Cork City was considered in depth and is found to be unworkable.
He was responding to questions from Cork South Central TD Michael McGrath on the OPW's proposal to protect the city from river and tidal flooding.
"The proposal of a tidal barrier put forward by others was considered in depth and is found to be unworkable for cost, navigational and environmental reasons as well as lacking upstream storage capacity in the likely future climate change scenario," he said.
The first phases of the flood defence works are being carried out at Morrisson's Island in tandem with an upgrade of the roads and footpaths in the area.
The Morrison’s Island scheme is being carried out by Cork City Council before the OPW takes over the €140m project.
The Save Cork City organisation is opposed to flood defence walls. They say an independent report they commissioned by UK hydro engineering company HR Wallingford on a tidal barrier at Lough Mahon costing up to €170m would be a better solution.
Minister Moran said in the Dáíl that is was technically possible to construct a barrier elsewhere, at either side of Great Island, but the estimated whole life cost of this of up to €1.7 billion also makes it a non-viable option.
"In light of the in-depth analysis on the tidal barrier option for Cork carried out by international experts, the position is that a tidal barrier is not a viable solution for Cork and cannot be considered further," he said.