The refugees came from the Australian offshore detention camps in Manus (Papua New Guinea) and Nauru, and were brought to the mainland for medical treatment.
They are being held at the Park Hotel in Carlton, where 22 of them now have Covid-19, with one hospitalised.
The Refugee Action Coalition's Ian Rintoul claimed the proper protocols of separating the infected from those without the virus had been ignored by Australian officials.
He said the Australian government has created a Covid incubator in the Park Hotel.
"It is the circumstances of detention which have resulted in them being exposed to covid, in the same way they were exposed to terrible mistreatment in Manus and Nauru, and it's time that this treatment was ended.
"The Covid crisis in the Park Hotel is just the final demonstration of the mistreatment of people who should have got safety and protection from 2013."
Last month, a statement from Australian Border Force said all refugees and asylum seekers were offered vaccines from August.
But the majority of refugees and asylum seekers held by Australia in detention centres, hotels and other temporary facilities, had not been fully vaccinated.