LARGE scale testing for COVID-19 was implemented as a matter of urgency on Sunday after a Mildura man returned a positive test for the virus at the weekend.
The man, aged in his 30s, had been told to monitor for COVID symptoms after attending an MCG match between Carlton and Geelong on July 10.
He had been seated in the same MCC members' reserve where another man with COVID-19 had been.
The Mildura man presented at Mildura Base Public Hospital's Emergency Department late Saturday night and a positive result for COVID-19 was confirmed in the early hours of Sunday morning.
It is believed he was among a group of three household members who travelled to the game.
Thousands of vehicles passed through a testing site that was hurriedly established on Sunday at the Mildura Recreation Reserve in response to the positive test.
Health authorities have warned the Mildura case is likely to require extensive testing of community members over coming days.
COVID-19 commander Jeroen Weimar said the Mildura man was "at least a Tier 2 contact, possibly a Tier 1 contact" with the other man with COVID-19 at the MCG.
Mr Weimar said authorities were working with the Mildura man to determine his movements after attending the AFL match.
"We'll view the movements, we'll view the CCTV, we'll look at the QR code information so I'm confident he was on our initial list of Tier 2 contacts, if not Tier 1 contacts and he would have received messages through that process," he said.
"On the basis of that household group if they are Tier 2 or Tier 1 exposure sites they will, of course, be under their own isolation testing protocols."
Mr Weimar said he was unsure with what symptoms the Mildura man presented at the hospital.
"Obviously we wanted to make sure it was a COVID positive case (then) a series of protocols go in place that we do with all our hospital departments," he said on Sunday.
"He is currently in the care of those physicians (and) we have protocols in place at the hospital to ensure the safeguarding of other staff and people in that hospital.
"He is safe, he is well secured and we'll work with him over the coming hours."
Victorian Premier Daniel Andrews said the positive COVID-19 case in Mildura highlighted how invasive the virus was.
"There is one in Mildura and that's about as far away from Melbourne as you are going to get and still be within our state," Mr Andrews said.
"It just goes to confirm the problem anywhere is potentially a problem everywhere and that's the reality we're living," he said.
"The problems out of Sydney have challenged us here and if there is a problem in Melbourne then there's every reason to believe that we have to (have) a very conservative approach to regional Victoria.
"I know it is incredibly frustrating for people who are a long way from Melbourne, but this virus can reach you as we see with this Mildura case.
"We will be across that as quickly as we possibly can, locking people down, providing them with support and all of those things.
"The Mildura case today just confirms that Victoria is a big state, but when it comes to the spread of this virus it is actually quite small and it can move to the furthest point of the state very, very fast."
Mr Andrews said he would not release any part of Victoria until he had advice that it would be safe to do so.
"I have no advice to shorten the lockdown in regional communities which I read to mean it would simply not be safe to do that -- that may change over the next 24 hours, let's wait and see," he said.
You only get one chance to go hard and fast, to act early, to act decisively -- that's what we've done.
"This Mildura case is obviously out of left field a bit, let's just wait and see how things unfold over the next two days."
Check coronavirus.vic.gov.au/exposure-sites to keep up to date with exposure sites in Sunraysia.
