Victoria's emergency management authority will oversee the state's coronavirus response as the number of confirmed cases continues to grow.
Another three Victorians were confirmed as having the illness on Wednesday morning after returning from the United States.
Carey Baptist Grammar School in Melbourne's inner east later reported a second of its staff members becoming infected, bringing the state's total number of cases to 22.
Premier Daniel Andrews says the state control centre has begun co-ordinating government agencies grappling with the virus outbreak, which has been categorised as a class two emergency.
Class one emergencies include natural disasters like bushfires and floods, while class two includes extreme heat and energy issues.
"The central co-ordination of our response is very important. We've learnt that many different times in different circumstances," Mr Andrews told reporters in Melbourne.
Emergency Management Commissioner Andrew Crisp said the control centre will collate intelligence on exactly how the issue is unfolding.
"Good information will lead to good decision making," he said.
Among the latest three infected people was a man in his 50s who became unwell upon returning to Melbourne from Seattle on Saturday on Virgin flight VA24.
He is recovering in home isolation and three close contacts - including two children - are also in quarantine.
The man visited the Mussel and Jazz Festival at South Melbourne Market on March 7 between 2pm and 3.30 pm then went to the Rebels and Lions rugby match at AAMI Park where he sat in section 9.
The other two cases were on flights which have had confirmed COVID-19 cases this week - UA0600 and QF94 - but are understood to have contracted the virus while in the US.
One, a man in his 50s who returned from Los Angeles on Friday, is a staff member at Yeshivah and Beth Rivkah Colleges at St Kilda East.
He worked for half a day while infectious on Monday and the school confirmed it would be closed on Wednesday.
The other new case is a woman in her 20s who travelled through the US and became unwell on February 29, after returning to Melbourne the same day.
She is also recovering in home isolation.
More than 1000 Victorians visited seven hospital clinics across Melbourne on Tuesday to be tested.
Health authorities are expected to set up 100 "pop up" coronavirus clinics across Australia as part of a $2.4 billion federal government response.
Health Minister Jenny Mikakos expects some may well follow the approach taken by a Melbourne GP who has been performing "drive through" tests in his clinic car park.
Victorian Treasurer Tim Pallas has also backed away from regular assurances he will deliver a surplus in the May budget, citing the "major public health crisis" amid other pressures.