What happens when a Covid case is detected?

With the demand for information around the announcement of two further cases in Parkes and Forbes on Monday, Western NSW Local Health District Chief Executive Scott McLachlan has explained the process that's followed once a case is detected.

He says venues will not be made public if the team is confident they have identified everyone who was there. He gave an example of a service station late at night where CCTV footage showed nobody else was in attendance.

"When we've identified a new case of Covid the team go through a rapid assessment to understand when they became infectious and where they might have been and very quickly contact those locations if we can - in some cases that's difficult," Mr McLachlan said.

That work is to ascertain whether health authorities are able to contact everyone who might have been at the location if there was somebody infectious there - and if there was a risk of contracting the virus.

"If we can't contact everyone that's when we'll list a venue as a venue of concern," Mr McLachlan said.

"That can take as little as 12 to 24 hours, some of those are coming out very rapidly, some of them are taking - because of those case interviews being complex - up to 48 to 72 hours.

"I know that's a long time to wait but we don't go out and notify people unless we can't contact everyone that's been at those venues."

That said, he does urge everyone to check the NSW venues of concern regularly.

"We've got growing numbers in the western region," he said.

When a venue of concern is listed on the website, it also provides instructions on what action you should take if you were there at that time.

Typically, casual contacts are asked to get tested immediately and self-isolate until they receive a negative result.

If the notification was quick, they're also asked to get a test on day 5 after potential exposure.

Testing is available at Parkes Showground 10am to 3pm daily.