Victorians in the greater Brisbane area should cancel any travel plans back to their home state and abide by a new three-day COVID-19 lockdown.
Anyone who has been in Brisbane, Moreton Bay, Redland, Ipswich or Logan council areas since January 2 "should not leave those areas until at least Monday", Victoria's Chief Health Officer Brett Sutton said on Friday afternoon.
Victorians planning to enter those parts of the sunshine state should also ditch their plans.
"All Victorians in these areas are advised to follow the guidance of the Queensland government and any Victorian with plans to travel to these areas should cancel them," Prof Sutton said.
Those who have arrived in Victoria from the greater Brisbane area since January 2 should get tested and self-quarantine until Monday, January 11 when a further assessment will be made, he said.
Earlier on Friday, Premier Daniel Andrews indicated it was unlikely Victorians wanting to return from those parts of the sunshine state would be able to once the hard lockdown takes effect.
A three-day hard lockdown begins in Brisbane and surrounding communities from 6pm on Friday following a positive COVID-19 test of a cleaner at a quarantine hotel.
The cleaner was diagnosed with the UK's highly infectious, mutant strain of coronavirus, prompting national cabinet to declare Queensland a national hotspot.
Implications of the Brisbane situation on Victoria's travel permit system are yet to be updated.
Meanwhile, Victoria has marked a second straight day with no new locally acquired COVID-19 cases, a result marred by a hardware malfunction delaying thousands of test results.
The sole new infection recorded in Victoria on Friday was in a returned traveller in hotel quarantine, bringing the state's active cases to 39.
But about 10,000 negative test results - mainly affecting those from regional areas - were held up on Thursday as Dorevtich Pathology had a technical fault.
Teams worked through the night to fix the outage, rectifying it by 3am on Friday.
Mr Andrews apologised for the delay and confirmed the results were beginning to be fed out to people on Friday morning and would appear in Saturday's figures.
It meant only 23,108 tests were received in the 24 hours to midnight on Thursday, down about a third on the 30,000-plus results seen daily over the past four days.
Victoria's total testing figure over the past week is almost 200,000, as the state tries to stamp out the Black Rock cluster.
The two-day streak with no reported community transmission has Mr Andrews upbeat that contact tracers are winning the fight against the 27-case outbreak linked to a Thai eatery in bayside Melbourne.
"There is a degree of confidence that we are close to running Black Rock to ground," he said.
The mystery case of a COVID-positive man in his 30s who attended Boxing Day sales at Chadstone Shopping Centre and the second day of the Test at the MCG is slightly tempering his optimism.
It has been linked to Sydney's northern beaches cluster, but authorities still aren't sure how the Melbourne man caught the virus.
If it weren't for that case, Mr Andrews said Victoria would potentially be further along in reopening the border to thousands of residents stranded in NSW.
"The moment that the health experts tell me it's safe to get those people back, that's exactly what we'll do."