Patients are being diverted from Peel Health Campus south of Perth, following the discovery of mould in its air conditioning system.
A total of 23 patients were relocated to other parts of the facility or other hospitals on Saturday after Peel Health Campus was notified about the presence of mould on Thursday.
WA Health Minister Amber-Jade Sanderson said ambulances carrying priority one patients had been diverted to other facilities, but the emergency department remained open for walk-ins.
Ms Sanderson said three operating theatres were out of action this weekend, which would impact some surgeries.
"Areas not affected are oncology and maternity services so it is at this stage contained to 32 patients who are in the high-risk area, who need to be relocated to other facilities," she said.
St John Ambulance WA has now dispatched a Multi Transfer Vehicle and several ambulances to support the transfer of patients to alternative facilities in the Ramsay Health Care network.
Patients, staff wearing PPE
Peel Health Campus chief executive Matthew Wright said an initial disinfection of the affected areas had been carried out and they would carry out more comprehensive remediation following feedback from health authorities.
Mr Wright said the pandemic had prepared the hospital well for its interim response.
"The safety of our patients, visitors and staff and community is our top priority and that is why we are taking a very thorough and considered approach to managing this situation," Mr Wright said.
"The community can be reassured that moulds are commonly found in the general environment and in most cases with a healthy person, their immune system can protect them from infection.
"As a precaution, staff and patients will be required to wear PPE and we are temporarily restricting visitors with some exceptions on a case-by-case basis.
"I know this information may be concerning to some people but I want to reassure you we are doing everything we can to fix the situation as quickly as possible to restore all clinical services for patients."
The South Metropolitan Health Service said it was aware of the situation and assisting with patient transfers to other hospitals in its network as required.
It comes after another private hospital in metropolitan Perth was forced to suspend its elective surgeries for a week in similar circumstances earlier this year.
Mount Hospital took the precautionary measure in February following the discovery of black mould in its air conditioning system, which required patients to be transferred from three wards, including its intensive care unit.
In a statement at the time, the hospital said that while the black mould presented a relatively low risk to healthy individuals, the risk to immunocompromised patients could be elevated.
