People are being warned to stay out of the water in Pilot Bay, due to a wastewater overflow this afternoon.
Warning signs have been put up on the stretch of beach where the water was polluted.
The cause of the overflow was a pipe blockage caused by wet wipes.
Water quality samples will be taken to check bacteria levels in the water, with results due on Tuesday. Until the results are in, people are urged to stay out of the water.
The warning signs will be removed from the beach once the tests confirm the water poses no health risk.