The source of a positive COVID-19 reading in Central West New South Wales sewerage has caused concern for local health authorities.
Testing numbers have risen dramatically over the weekend across the Dubbo and Mudgee areas.
The Western NSW Local Health District (WNSWLHD) has been urging residents to be on high alert as they search for the cause of the positive readings.
More than 1,400 tests have so far been carried out at Dubbo as part of the latest blitz, while about 500 were conducted in Mudgee.
The numbers are a big increase on usual testing numbers, according to local health authorities.
The positive COVID-19 sewerage readings have occurred twice in one week for both regional centres.
WNSWLHD chief executive Scott McLachlan said there either is, or was, a positive case in the region.
"It might have just been a one-off contractor or truck driver or someone coming through if it was just one sewage test," he said.
Mr McLachlan said people needed to consider if, and how, they may have come into contact with the virus.
"If you think that you've been in a place that you might have had some exposure, then please come and get tested," he said.
Visiting from the lockdown area
Local police have increased their search for people from lockdown areas coming into the Central West.
Over the weekend, Dubbo police have caught three people from the Central Coast, which is part of the Greater Sydney lockdown, attempting to enter the area.
They were issued with infringement notices and turned back to the Central Coast.
Police are regularly checking vehicle registrations to ensure travellers are from the local area, but there are concerns about ongoing non-compliance.
"People just don't get the message and continue to to try to put everybody in danger," said NSW Police Western Region Commander Assistant Commissioner Geoff McKechnie.
"We are catching as many as we can, but we need communities helping as well and we really need people to deter relatives as well as friends.
