Staff at a childcare centre in Sydney's north-west are being tested for the deadly coronavirus.

The centre is the Banksia Cottage in Macquarie Park, near the BaptistCare nursing home where an aged care worker and a 95-year-old woman contracted the disease.

The older woman, who lived at the facility, died in hospital on Tuesday.

NSW Health Minister Brad Hazzard confirmed today another patient at the aged care facility has contracted the disease.

The 70-year-old patient had no contact with the infected aged care worker.

"I think at point it is fair to say that we do have an evolution happening in the spread of this virus," Mr Hazzard said.

"New South Wales Health is doing everything they can to try to still contain it, but we do know that containment is likely to be an unlikely outcome, so we need to work constructively with the community, to continue our effort to emphasise to the community that it is a partnership."

It is believed cross-contamination between the childcare centre and aged care centre may have occurred during a visit by children to the nursing home.

"I would like to say that it isn't surprising that we will identify additional cases in that aged care facility and that reflects exposures that have occurred prior to any interventions, so we are actively screening and looking for cases, and we will continue to do so," NSW Chief Medical Officer Kerryn Chant said.

The aged care facility is being monitored daily for any patients or staff members showing signs of respiratory illnesses.

Visits of children from the childcare centre to the nursing home have been put on hold until further notice.

Mr Hazzard also said today another healthcare worker has been infected by the virus.

A young registrar who was at the same conference as the 53-year-old infected doctor from Ryde Hospital has tested positive to COVID-19.

More than 70 healthcare professionals attended the radiology seminar on February 18.

Source: 9News