“Further testing has been urgently arranged to confirm the diagnosis,” the department of health said in a statement. “Until that time, the department is treating this as a positive case and acting accordingly.”

Contact tracing has begun in the meantime, and the department said a list of potential exposure sites would be published once confirmed.

The man and others in his household are isolating at home. Those close contacts were also being interviewed and tested. The department is working with interstate health authorities to determine the likely source of the infection. Anyone with symptoms is being urged to get tested.

The new Victorian case comes as health authorities in New South Wales continue their efforts to track down the “missing link” between a case of community transmission and a returned traveller from the US. Sequencing revealed their cases of the virus match, but contact tracing has failed to reveal any opportunities for transmission between the two, leading them to believe there is an unknown case linking them.

While no new community cases were identified in NSW in the 24 hours to 8pm Monday, authorities remain concerned. Restrictions are in place until 17 May for greater Sydney, including Wollongong, the Central Coast and the Blue Mountains.

People in NSW aged 40 to 49 are able to register to get the Pfizer vaccine at a new Covid-19 mass vaccination hub that opened at Sydney Olympic Park on Monday. A further 351,000 Pfizer doses arrived in Australia on Monday and will be tested by medical regulators for quality and safety.

Data published on Monday night shows 2,663,221 doses of vaccine have been administered in Australia.

This week the Vaccine Operations Centre is expected to triple the allocated doses from 50 to 150 per week for 3,000 lower volume general practices, double the allocated doses from 100 to 200 per week for 1,000 medium-volume general practices, and double the Pfizer doses to states and territories to support vaccination for those under 50.