The local beach was the only one of Northern Ireland’s 23 beaches that failed to meet European standards for bathing, in research carried out by the Marine Conservation Society.
Councillor Patrick Clarke said: “This has gone on long enough, the Council must step in and address the water quality problem at Newcastle Beach. The time for making excuses has long past, action is needed before the situation gets any worse.
“Part of the contamination is coming from sewage pipes and increased discharge of waste, so I recognise that it is a combination of factors, but the situation is now making Newcastle hit the headlines for all the wrong reasons.
“At a time when Tourism is a major source of revenue for the area, we cannot afford to take this matter lightly. Not only does the water quality need assessed, but the beach needs attention with a concentrated effort to clean it up.
“I am calling on Down District Council to stop accepting this poor report as the norm and to urgently deal with the conversation.”