Residents across the north coast of NSW and into the western regions are being encouraged to be more vigilant than ever for signs of COVID-19, after indications the virus is active in several communities.

NSW Health has announced that surveillance programs on sewerage systems in Dubbo, Armidale and Woy Woy all detected trace fragments of the virus during the past week, while new cases have been recorded in the Central Coast and Newcastle.

In a press conference this morning (Thursday 5 August), the Premier announced NSW had recorded 262 new locally acquired cases of COVID-19 in the 24 hours to 8pm last night, including one in Newcastle.

262 new locally acquired cases were announced at a press conference this morning by Premier Gladys Berejiklian.

A further four cases in Newcastle were added to the list by morning and while the source of infection is under investigation, it is believed a gathering on Blacksmith beach on Friday night may be the culprit.

To prevent potential spread, health officials announced new restrictions will be introduced for Newcastle, Lake Macquarie, Maitland, Port Stephens, Singleton, Dungog, Muswellbrook and Cessnock from 5pm tonight.

The rules in place for these areas are the same that are already in place across Greater Sydney - including stay at home orders and bans on social visits - and will remain until Friday 13 August.

In addition, residents in the locations where virus fragments were identified in sewerage treatment plants, including the one in Dubbo serving around 37,000 people, are being urged to come forward for testing.

Chief Executive for the Western NSW Local Health District Scott McLachlan said there were currently no known cases of COVID in Dubbo at this stage, but because the sewerage detection couldn't be traced to an individual, it was important testing numbers were high.

"High testing rates help us to detect any cases of COVID-19 as early as possible," Mr McLachlan said.

"We are increasing resources and capabilities at the drive-through testing site at Dubbo Showground, which is open from 8am to 4pm every day, and we ask everyone to please be patient while waiting for their turn.

Western NSW Local Health District Chief Executive Scott McLachlan implored regional NSW residents now is the time to stay vigilant.

"I encourage anyone who is symptomatic to come forward for testing, which is free and does not require an appointment.

"Please ensure you wear a mask while at the testing site, and then immediately isolate until you receive a negative result."

According to Mr McLachlan, the detection of virus fragments in sewage can be due to shedding of the virus by someone who may have previously had the illness and may no longer be infectious.

It can also be the result of a person with COVID-19 who may have visited the community and has since left the area.

As well as being present in stools, viral fragments can enter the sewer when washed off hands and bodies through sinks and showers. Usual sewage treatment processes inactivate, or kill, the COVID-19 virus.

The testing clinic at the Dubbo Showground will be open today and tomorrow (Friday 6 August) from 8am-4pm.

For all the latest information about COVID-19 in NSW, click here.