The NSW-Victorian border closure will remain in place for some time, and movement between the states could be further restricted if seeding occurs in southern NSW.
Victorian Premier Daniel Andrews said wastewater monitoring of border communities was occurring on a daily basis.
"If we started to see seeding further south right into southern NSW then there's every chance we would look to go even further," he said.
"And those border communities, as much as it's difficult to live under these conditions, the last thing you want is for this virus to get into those regional communities, the last thing you want is more and more incursions, more virus from Sydney and NSW."
Mr Andrews said the reasons residents could move within the border bubble could potentially change, as could the list of local government areas included in the border bubble and the list of essential workers.
"...We will make the decisions however tough they are to keep our state safe, the notion of freedom of movement between the two states ain't happening anytime soon because it just wouldn't be safe to do that," he said.
"Now I appreciate having grown up not far from that border, my mum is only 45 minutes from that border, it is very challenging for border communities to not have all the freedom of movement that is a normal part of their life.
"The border doesn't exist for so many of those communities, they shop and work and get healthcare and get educated, all social and community sports and all different things.
"We know that there are impacts there and that's why we will very soon announce more business support for the whole state particularity those in metro Melbourne who are most affected by these most recent extensions..."
It comes as cases were detected in the southern NSW region of Goulburn and Queanbeyan.
Mr Andrews would not comment on the NSW government's handling of the current COVID outbreak or their comments about easing restrictions when possible.
COVID-19 fragments have been found in wastewater for the third time, leading Goulburn Valley Health's chief executive and the Victorian government to renew calls for residents to be tested.
Matt Sharp said COVID-19 was detected in wastewater samples taken on August 10-11, 13 and 16.
"Anyone from the greater Shepparton area who is unwell with any symptoms of COVID-19, no matter how mild (such as fever, chills, cough, sore throat, runny nose, loss of sense of smell), should be tested immediately and go home," he said.
"People should stay at home until they get the result of their COVID-19 test. Do not go about your normal day-to-day activities such as work or going out in the community.
"Please do the right thing and do not place your family members, friends, colleagues and the broader community at risk."
Victorian Premier Daniel Andrews said the high number of daily cases show the system is working.
He said said 57 seems a big number but the vast majority had been in isolation for their infectious period.
Mr Andrews said many had tested positive on their day-13 isolation test.
"That's exactly what we want, that's the system working," he said.
Mr Andrews said those people who had tested positive of day 13 of their isolation would now have to isolate for a further 14 days and thanked them for their efforts.
It comes as Victoria recorded its worst day yet of the Delta outbreak with 57 cases.
The figure is more than double yesterday's 24 case tally. Of the new cases in Victoria 13 were infectious while in the community.
Three of the cases have not yet been linked to known outbreaks.
NSW recorded 681 cases and one death in the 24 hours to 8pm yesterday.
Of which 87 were infectious while in the community. The isolation status of 459 cases remain under investigation.
IN OTHER NEWS:
Today marks Melbourne's 200 day of COVID lockdown.
Health Minister Martin Foley on Wednesday said there were more than 10,000 close contacts of known COVID-19 cases due for day-13 testing in coming days and it was expected that the case numbers would be large, but most people were in isolation.
- with AAP
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