A staff worker at The Palms Aged Care centre at Kirrawee, who has tested positive to COVID-19, was unvaccinated.
NSW Health's Dr Jeremy McNulty revealed this at the state government's daily media conference.
It will be mandatory from September 17 for all residential aged care workers to have received a minimum first dose of a COVID-19 vaccine.
Health Minister Brad Hazzard was asked later about reports of workers mounting a class action against this direction.
Mr Hazzard responded, "We have had to step up and tell a number of different health workers and aged care workers that you have to accept being vaccinated or you can't work in that particular area, and that's continuing".
Management of The Palms Aged Care centre at Kirrawee have detailed steps that have been taken to contain COVID-19 after a staff member tested positive.
A statement on the centre's website on Thursday read:
"The South Eastern Sydney Local Health District informed us on Tuesday afternoon (July 20) that a member of our staff tested positive in a COVID-19 test.
"The person is now in isolation, as are the other close contacts in her team and the 65 residents in the facility, as a safeguard.
"Testing of residents and staff will continue on a regular basis and the facility has undergone a deep clean and is in full lockdown, with staff wearing personal protective equipment to allow them to continue caring for the residents, all of whom are fully vaccinated.
"NSW Department of Health is vaccinating the less than 10 percent of the 65 staff in the facility who remain unvaccinated."
Residents of The Palms Aged Care centre at Kirrawee are in isolation after a staff member tested positive to COVID-19.
The residents are being treated as close contacts while the situation is further assessed.
Most residents have been vaccinated.
Temporary fencing has been erected around the facility on President Avenue, there is additional security and no visitors are allowed.
A media statement posted on the website of The Palms Aged Care reads:
A staff member of The Palms, Kirrawee was this evening diagnosed with Coronavirus Disease 2019 (COVID-19).
The South Eastern Sydney Local Health District are working closely with the facility to ensure the health and safety of all residents and staff is maintained.
In order to reduce the risk of further spread of COVID-19 NSW Health has recommended that no visitors or non-essential staff are permitted to enter The Palms, Kirrawee until further notice.
Our nursing staff will have the recommended personal protective equipment to allow them to care for our residents while preventing any spread of the infection.
At this stage, out of an abundance of caution, we are treating all residents as close contacts of the affected staff member whilst we assess the situation in more detail.
Staff will be implementing strict infection control measures, and carefully monitoring residents for any symptoms such as fever, cough, sore throat or shortness of breath.
Residents, and affected staff, will be tested on-site within the next 24hrs.
The residents are currently in isolation awaiting testing with the assistance of the Public Health Unit.
Mathew Hafford, Operations Manager says the health, safety and wellbeing of our residents and staff of The Palms is of the highest priority and everything possible is being done to help contain and control the outbreak as quickly and safely as possible.
We have and will continue to operate on maximum alert levels.
Mathew Hafford moved to assure residents and their families, as well as our dedicated staff and the community, affected by the impact of the virus at The Palms that we will continue to deliver safe, quality care and services to all residents while the situation is being closely monitored.
"Thankfully, most of our residents are fully vaccinated against COVID-19," he said.
"We recognise this is a difficult time for families and friends, but we are committed to providing the latest information and updates, and alternative methods of connecting with their loved ones such as via the CareApp, Facetime, email and phone, Mathew Hafford said.
"We thank the families and friends of our residents for their understanding and will continue to work and communicate closely together.
"Please be assured The Palms staff and the team from The South Eastern Sydney Local Health District are doing their absolute best and we want to acknowledge their support and professionalism during this challenging period."
Further information is available via the following website www.health.nsw.gov.au