A ban on swimming is in effect for Dollymount Strand in north Dublin due to the discharge of sewage from a wastewater treatment plant.
The discharge followed stormwater overflow at Ringsend Wastewater Treatment Plant which was caused by heavy rainfall in recent days.
Dublin City Council said swimming in water at Dollymount Strand may cause illness.
The ban, which was issued on Tuesday, is expected to be in place for four days.
Located on North Bull Island, Dollymount Strand is the closest large beach to Dublin city.
Water quality had been assessed as excellent at the beach in the majority of samples taken by the local authority in recent years prior to the current swimming ban.
