Workers in high-risk industries will be randomly tested for coronavirus as Victoria continues to slowly ease restrictions.
Premier Daniel Andrews on Wednesday announced all medium and large businesses in the meat, poultry, seafood processing and supermarket and distribution sectors will have to test 25 per cent of staff each week.
Regular testing will also occur in aged care after an agreement was struck with the federal government.
About 50 per cent of workers at metropolitan Melbourne aged care facilities and 25 per cent in regional Victoria will be tested weekly.
Workers will not be required to self-isolate unless they receive a positive result.
Wastewater will also continue to be monitored at more than 30 sites.
Jeroen Weimar from the Department of Health and Human confirmed a COVID-19 positive sewerage sample was identified at Anglesea, despite the Surf Coast having no known active cases.
A testing site has opened at Anglesea Town Hall.
"We know there is either someone who has had coronavirus in the Anglesea area or someone who has passed through, but it may also be someone who is not yet aware that they have the virus," Mr Weimar said.
He encouraged anyone in the Anglesea area "who has any symptoms whatsoever, who feels remotely unwell" to get tested.
It comes as Victoria has recorded 13 new coronavirus cases and four more deaths, bringing the state's death toll to 798 and the national figure to 886.
The latest victims are a woman in her 70s, a woman in her 80s and a man and woman in their 90s.
Two of the four deaths are linked to outbreaks in aged care facilities, where 147 cases remain active among residents and staff.
Of the 13 new cases, two are linked to a worker from the Butcher Club at Chadstone shopping centre.
The worker was contagious between September 23 and 26, when they worked 6am to 6pm shifts at the butcher and used public toilets in the vicinity.
The Butcher Club, Coles Chadstone, Chadstone shopping centre fresh food precinct and Woolworths Ashwood have been added to the high-risk coronavirus hot spots around Melbourne.
The new cases bring Melbourne's 14-day average down to 16.4.
There remain 21 mystery cases between September 14-27, all in Melbourne.
Melbourne's 14-day average needs to drop below five and there must be fewer than five mystery cases for a fortnight before the state eases restrictions further.
The premier said this was not likely to happen until October 19.
There are 44 Victorians fighting the virus in hospital, including six in intensive care, three of whom are on a ventilator.
Some 17,937 people were tested for the virus on Tuesday.
"That is a very strong number and can I personally acknowledge and thank each and every one of those almost 18,000 Victorians," Mr Andrews said.
