Victoria has recorded just two new locally acquired Covid-19 infections as health authorities race to find the source of two unlinked cases who visited major exposure sites.
The latest cases recorded up to midnight on Saturday take the outbreak, which now consists of four clusters, to 72.
The two local cases are the lowest daily update since the outbreak began 13 days ago. There were however six cases detected in hotel quarantine.
There were 29,816 people tested for the virus in the previous 24-hour period while nearly 20,000 vaccine doses were administered.
One of the two unlinked cases announced on Saturday was a regular visitor to Craigieburn Central shopping centre while infectious, health authorities confirmed.
That person's partner is the other unlinked case and is a construction worker, which has prompted the closure of a Melbourne building site, affecting 170 workers who are now all considered primary close contacts.
On Saturday testing chief Jeroen Weimar said he was "most concerned" over the cluster infected with the highly-infectious Delta variant, which grew by two to nine.
Health authorities have yet to find the cluster's source, with the Doherty Institute's infectious diseases expert Professor Sharon Lewin saying it was likely it had come from hotel quarantine in another leak.
She said there was no evidence pointing to the Victorian family at the centre of the cluster picking up the virus while on holiday in NSW. She said it was highly unlikely the virus was festering undetected in other states.
The state government will announce further details related to the two new cases later on Sunday.
Melbourne is in its second week of strict lockdown and Health Minister Martin Foley has remained non-committal about guaranteeing restrictions will ease come June 10.
There are now 390 sites where exposure to the virus may have occurred.
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