These workers have been targeted by the NSW Government following a number of COVID-19 clusters across the state, including at two aged care facilities in Sydney and at a childcare centre in Blacktown.

These clusters have left dozens of people infected and a number have died.

NSW chief health officer Dr Kerry Chant on Monday morning urged anyone with the mildest of symptoms "err with caution" and get tested.

"Anyone who is a health care worker, working with vulnerable groups, disability care worker, anyone who's working in an institution with vulnerables, in prisons or detention centres, or in schools - if you develop any symptoms with fever, shortness of breath, cough, sore throat we do urge you to come forward for testing," she said.

"The rationale for that is the implications of you introducing COVID into those institutional settings can be quite significant.

"We are aware that in those settings we see quite an application and spread of COVID-19 so we want to interrupt spread in those settings at the earliest possible time.

"We want to make sure people feel comfortable coming forward for testing.

Dr Chant acknowledged the COVID-19 virus is very challenging one to control.

"We have to be honest and open that it's going to be a challenge to pick up every case," she said.

Dr Chant said increased testing will allow health authorities to recognise the early stages of an outbreak and to conduct contact tracing to prevent further community transmission.

At Anglicare's Newmarch House in Sydney a worker with very mild or no symptoms entered the facility six days in a row.

Since then 41 people, including residents and staff, have become infected with COVID-19 and two have died.

"It's a cautionary tale for anyone working in aged care or with vulnerable people how the most minor of symptoms please do not attend work, get tested," Dr Chant said.