Widespread pollution is likely at many Illawarra beaches on Monday due to significant rain and stormwater run-off.
People are urged not to enter the water at Bellambi and Corrimal beaches in Wollongong, and Surf and Werri beaches in Kiama due to the likelihood of pollution.
Pollution is also possible at: Austinmer, Thirroul, Bulli, Woonona, North Wollongong, Wollongong City, Coniston, Fishermans and Port Kembla beaches in Wollongong.
Further south, pollution is possible at Warilla, Shellharbour, Boyd Jones and Bombo beaches.
"Rainfall data has been used to predict the likelihood of bacterial contamination at beaches in the Illawarra region," Beachwatch says.
"The most obvious signs of stormwater pollution are water discolouration as well as debris in the water and on the tide line."
Well above average rainfall was recorded in Bellambi during April, with 142.8 millimetres. The long-term median is 96.5mm.
Albion Park had slightly higher rainfall at 84.0mm, compared to a median of 74.8mm. While Kiama received below average rain at 140.4mm compared to an April median of 130.7mm.
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