The new case, a woman who worked as an authorised officer at the Holiday Inn at Melbourne Airport, was the only new infection recorded in Victoria overnight.
More than 11,000 tests were conducted in the past 24 hours and there are 20 active cases in the state.
The worker was first tested at the end of her shift on Thursday, February 4, where she returned a negative result.
The woman then returned to work on Sunday morning and later developed symptoms.
She was tested and subsequently returned a positive result for COVID-19.
“The individual is being interviewed and a full public health response is underway,” the Department of Health said in a statement.
“We are contacting Holiday Inn Airport workers and others who are considered primary close contacts.
“They are required to immediately isolate, get tested and remain isolated for 14 days.”
The woman’s case is the third infection to seep out of Victoria’s hotel quarantine system.
A hotel quarantine worker in Melbourne has tested positive to coronavirus. (Nine)
The Holiday Inn was not one of the quarantine hotels used to house the Australian Open contingent.
“We’ve been preparing this for over a year, it will be one of the safest places to be through the health screening that we are doing,” he said.
“The way the site is set up, everyone will be safe, protected and on top of that, getting back to seeing some great tennis.”
Health authorities are now scrambling to identify exposure sites where the woman attended while possibly infectious.
Marciano’s Cakes: Maidstone – 9:45am – 10:25amDan Murphy’s: Sunshine – 5:50pm – 6:30pmOff Ya Tree Watergardens: Taylors Lakes – 1:17pm – 1:52pmDan Murphy’s: Sunshine – 6:50pm – 7:30pm
Testing capacity near exposure sites will be scaled up from today, with increased opening hours, additional staff and pop-up sites to be confirmed, the Department of Health said.
The new arrivals will see up to 440 ADF personnel work across 22 hotels in the state.
Fifty troops have now arrived to assist with the program after being held up by delays.
Defence Minister Linda Reynolds said there was a problem with one of the aircraft.
“We were sending 63 troops from Townsville’s 3 Brigade and the C-130 Hercules aircraft in Townsville had a system’s fault,” Ms Reynolds told Today.
“However, we got 50 of those 63 (troops) to Victoria overnight and we are now taking that number over the next few days up to 430.
“So, yes, there was a delay of a few hours last night but we got the troops to Victoria.”
The arrival of the troops follows a request by the Andrews government on January 29 to the Commonwealth, asking for military support to help Victoria Police manage the state’s hotel quarantine program.
The ADF will help police with residents arriving and departing from the quarantine hotels.
They will also help to document staff movements, manage baggage and check the temperature of workers before their shifts.