Green Party leader Roderic O'Gorman has said that urgent action is needed to prevent Ireland’s largest saltwater lake from becoming a toxic "goo lagoon".
He said that Lady’s Island Lake in Co Wexford is "highly-polluted" according to a report from the Environmental Protection Agency in January.
He said the EPA has been studying the lake for the last two years and that the report "makes grim reading".
Speaking in the Dáil, Mr O'Gorman referenced media reports that said the lagoon’s glow can be seen from space, and said that nutrient run-off is a problem.
Mr O’Gorman said that the report included a newspaper article from 1983 describing pollution in the lake.
"This has been a problem in the making for over 40 years, a problem that has been allowed to continue," he said.
"All the state mechanisms have failed to protect Lady’s Island’s Lake.
"If agricultural run-off is the recognised driver of this pollution, will you task the Minister for Agriculture take a lead here and will you agree with me that it must be a priority to reverse the pollution of this lake?"
He said that the solution now needs the "political clout" that a minister brings.
Mr O’Gorman described it as an "ecological disaster" that is happening in real-time.
Last month, marine biologist and co-author of the EPA report into the condition of the lagoon Dr Brendan O'Connor said from many points of view the lake is "dead".
The cause, Dr O'Connor said, is excessive nutrients in the water which give rise to the high production of algae, which grow at such a density that they block out the light and stop the plants that were growing on the lakebed.
Responding to Deputy O'Gorman in the Dáil, Taoiseach Micheál Martin agreed that a "specific action plan" should be developed for the lake.
"That has to involve a number of stakeholders," he said.
"Not just agricultural stakeholders but obviously they would be key."
He said that the Minister of State for Biodiversity should lead with the Minister for Agriculture and Minister for Climate.
"It has to be cross-departmental," he said.
"It has to be a whole of government approach."
Mr Martin said it was clear that a solution would have to involve farmers.
Mr O’Gorman said: "This time we have to do something different."
He said political leadership was needed to address fears that the lake would become a "dead zone for nature".
