Above normal E. Coli bacteria levels have been found in the water at Dover Harbour.
The Port of Dover have closed the area to swimmers and water-based activities.
In a statement, the Port said, "We would like to inform our Community that unfortunately standards were not met following our routine tests. There have been above normal E.coli bacterial levels indicated in these samples."
There are currently no reports of ill health.
The Port is working with external agencies in order to lift the restriction at the earliest opportunity and have apologised for any inconvenience caused.
For further information on Government bathing water quality standards click here.
Further information can also be found on the NHS website or contact NHS 111.