Emergency text messages are being sent to people in Keilor Downs and Broadmeadows, encouraging people to get tested.
The state government confirmed on Saturday it was seeking legal advice about whether it could make returned travellers in hotel quarantine get tested, a day after it was revealed 30 per cent in Victoria were refusing to do so.
"It's the government's view that all returned travellers should be tested," a government spokeswoman said.
"Following yesterday's decision at National Cabinet, Victoria is getting legal advice to explore all options."
Victoria's hotel quarantine program tests travellers on arrival and the 11th day, the government said.
Over the border in NSW, returned international travellers who refuse to have the test on day 10 must stay an extra 10 days in quarantine.
NSW has a two per cent test refusal rate, authorities said on Saturday.
Victorian Opposition leader Michael O'Brien said it made no sense that people could refuse the test, and if they did, they should pay for their hotel stay.
"If people in quarantine refuse a test how about we just make them pay for their own stay, and I think that'll sort it out pretty quickly," he told reporters on Saturday.
Victoria has ramped up testing with its focus on 10 suburbs with high community transmission - Keilor Downs, Broadmeadows, Maidstone, Albanvale, Sunshine West, Hallam, Brunswick West, Fawkner, Reservoir and Pakenham.
More than 736,000 total tests had been done to date on Friday.
Meanwhile, almost 5000 thermometers are being shipped to Victorian vacation spots as the state enters the school holidays.
Some of the 200 specialist medical and support personnel from the Australian Defence Force are understood to have arrived in Victoria to help with the state's coronavirus woes.
More than 1700 people have recovered from the virus in Victoria, while 20 have died.
People in Australia must stay at least 1.5 metres away from others. Check your state’s restrictions on gathering limits.
Testing for coronavirus is now widely available across Australia. If you are experiencing cold or flu symptoms, arrange a test by calling your doctor or contact the Coronavirus Health Information Hotline on 1800 020 080.
The federal government's coronavirus tracing app COVIDSafe is available for download from your phone's app store.
SBS is committed to informing Australia’s diverse communities about the latest COVID-19 developments. News and information is available in 63 languages at sbs.com.au/coronavirus.