Health authorities on Tuesday declared an outbreak of COVID-19 in the general medicine ward at Canberra Hospital.
Twelve patients and five staff have so far tested positive to coronavirus, a Canberra Health Services spokeswoman said.
"Once an outbreak is declared, staff on the ward wear N95 masks in clinical spaces to minimise transmission. Air purifiers are also deployed, all patients are placed on a PCR testing schedule and all staff who work in the area are also offered a PCR test," the spokeswoman said in a statement.
"We will continue to closely monitor the situation and if necessary, introduce further measures to protect staff and patients."
The outbreak was declared on ward 7B, which is in building 1.
Health minister Rachel Stephen-Smith said on Wednesday there was a total of 32 patients in hospital with COVID-related issues last Friday.
She said she encouraged people to test prior to visiting those in hospital and to wear a mask.
A mask requirement was dropped for Canberra Health Services staff in February, except in circumstances were they provide direct patient care and need precautions to limit the risk of COVID transmission.
Canberra Health Services chief executive Dave Peffer in early April warned staff the ACT was likely in the middle of a COVID wave.
"Things could be turning. Updated numbers suggest the ACT is in the midst of an [Omicron] XBB.1.5 wave. Our hospitalisations are trending up, with the week-to-week rise being the second fastest since mid-December," he wrote at the time.
The ACT appeared to have passed a peak of COVID-19 infections in late May, data on the seven-day rolling mean released last week by health authorities showed.
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