Victoria's Holiday Inn hotel quarantine outbreak has hit double figures, with two household contacts of infected workers testing positive for Covid-19.
The Victorian Department of Health today reported the two new infections were linked to the hotel at Melbourne Airport.
They are both household primary close contacts of previously confirmed Holiday Inn staff cases.
The outbreak now stands at 10 and includes three workers, two primary household close contacts, two released guests and a family of three who contracted the virus overseas.
It comes after the cases of a third Holiday Inn worker and second former guest, first reported yesterday afternoon, were officially added to Victoria's tally earlier today.
The department has also issued a new health alert asking anyone who visited the Sunbury Square Shopping Centre on February 5 between 3.40pm and 4.30pm (local time) to get tested and isolate until they receive a negative result.
They described the move as a "precautionary approach" after a hotel quarantine worker visited multiple stores while infectious.
The advice contrasts with that of other exposure sites, where people who attended must get tested and isolate for 14 days regardless of the result.
Anyone who visited the Sunbury shopping centre outside the timeframe is not considered to be at risk but should monitor for symptoms and get tested if they develop.
Two banks at Glen Waverley in Melbourne's southeast have been added to the list of potential exposure sites, which are spread across the city.
It is unclear whether the banks were visited by either the hotel worker, former guest or other previously announced cases.
The outbreak has forced the hotel's closure until further notice, while plans to increase the state's weekly cap on international arrivals from 1120 to 1310 from next week have been put on hold.
Authorities suspect a nebuliser, which vaporises medications or liquids into a fine mist, may be to blame for the outbreak.
The medical device was not declared by one of the family members in quarantine, who has an underlying health condition and was taken to intensive care on Tuesday.
Covid-19 Quarantine Victoria Commissioner Emma Cassar said the guest would have been taken to a medi-hotel if they had reported it.
More than 135 hotel staff were stood down and told to get tested and isolate at home for 14 days, while 48 guests were moved to the Pullman Melbourne to quarantine for at least another three days.
Chief Health Officer Brett Sutton said it was possible everyone on that hotel floor had been exposed to the virus through the air and warned more cases would likely be unearthed.
There have been cases of Covid-19 transmission across three Victorian quarantine hotels within a week, with three confirmed to be the more infectious UK strain.
Australian Medical Association president Omar Khorshid said the UK strain had "blown open cracks" in hotel quarantine infection controls.