Sydney health authorities have issued health warning the residents of some parts of Sydney on Thursday night.

A public health warning has been issued to residents in north western and western Sydney after traces of the Wuhan virus were found in tested sewage at two local pumping stations.

New South Wales Health is urging people from an extensive number of suburbs covered under the sewerage systems – including Rouse Hill, Box Hill, The Ponds and Quakers Hill – to come forward for testing.