NSW Health has issued a warning for almost 40 suburbs in south-western Sydney after fragments of coronavirus were discovered in wastewater.

Residents have been told to watch for symptoms of the virus and to come forward for testing immediately.

“(Residents) are being urged to come forward for testing if they have any symptoms after fragments of the virus that causes COVID-19 were detected at the Liverpool sewage treatment plant,” NSW Health said in a statement.

The affected areas are Abbotsbury, Austral, Bardia, Bonnyrigg Heights, Carnes Hill, Cartwright, Casula, Catherine Field, Cecil Hills, Cecil Park, Chipping Norton, Denham Court, Edensor Park, Edmondson Park, Elizabeth Hills, Gledswood Hills, Glenfield, Green Valley, Hammondville, Hinchinbrook, Holsworthy, Horningsea Park Hoxton Park, Ingleburn, Len Waters Estate, Leppington, Lurnea, Liverpool, Macquarie Links, Middleton Grange, Miller, Moorebank, Pleasure Point Prestons, Warwick Farm, Wattle Grove, West Hoxton, Varroville and Voyager Point.

The detection of the virus could reflect the cases that have been diagnoses in the recent weeks, however authorities are “concerned” there could be active cases in the community.