Two more Covid-19 cases have been diagnosed in Victoria, linked to the growing Holiday Inn cluster, which now stands at 10.
The two infections are household contacts of a known case, a worker who had previously tested positive.
Victoria's health department confirmed the new infections via Twitter.
"Interviews are under way and known exposure sites will be published online … as soon as possible," authorities said.
Three workers and two residents, both released from quarantine before testing positive, were previously diagnosed with coronavirus, and linked to the outbreak.
A family of three had earlier been identified as the epicentre of the hotel cluster. They were infectious before arriving in Victoria.
One of the residents who tested positive after being released from quarantine visited Commonwealth and HSBC banks in Glen Waverley.
They join several venues in Sunbury, including a busy shopping centre and a bottle shop, which were added to the alerts list this week.
The Holiday Inn at Tullamarine was closed on Wednesday for "terminal cleaning" and patrons were evacuated after the virus escaped into the community from the establishment.
Guests are being moved to the Pullman Hotel in Melbourne.
Victorian Premier Daniel Andrews earlier revealed anyone who spent 15 minutes or more at the Holiday Inn between January 27 and February 9 was considered a close contact and must isolate for 14 days.
The closure has also plunged more than 130 staff into isolation.
"If you are in hotel quarantine and you are being moved to a new hotel because we are doing a terminal clean of the Holiday Inn, you will have to continue your quarantine for at least three days," he said.
"It may be the full 14, but at this stage it will be at least three days and then, subject to testing and the evolution of this theory, we will keep people informed."
Victoria's chief health officer Brett Sutton said authorities were working on the hypothesis that the three cases were linked to exposure with a medical device called a nebuliser.
"It vaporises medication or liquid into a very fine mist," Professor Sutton said.
He said if it was used for medication, and someone was infectious, the device could cause fine particles to be suspended in the air that could be breathed in.
"We think the exposures are all related to the use of a nebuliser whereby the virus was carried out into the corridor and exposed the authorised officer, the food and beverage service worker and also the other resident," he said.