Bathers have been told not to swim near the slipway on the right-hand side of Tax-Xama, St Paul’s Bay, because of seawater pollution.
The Environmental Health Directorate said microbiological parameters in the seawater had been exceeded.
Environmental Health Officers are investigating the source of contamination. The duration of the contamination cannot be predicted at this stage.
Warning signs have been set up in the area.
People were also urged to avoid swimming in the area last October, because of a sewage overflow.