Victorian businesses flouting QR code COVID-19 check-in rules will face new on-the-spot fines.
Authorities are still waiting on results from the contacts of Melbourne's most recent virus case and have found some failed to use the QR code system, hampering contact tracing efforts.
Businesses breaking the rules will face a $1652 on-the-spot fine, and further penalties of up to $9913 and prosecution for repeated breaches.
Checks last week showed more than a third of businesses are not complying with QR code rules.
In April, authorities checked more than 4000 cafes, shops and restaurants, issuing 165 enforcement notices and 300 warnings.
The breaches included a lack of signage, failing to use QR codes, and not having a COVID-safe plan.
While most businesses are doing the right thing, Acting Police Minister Danny Pearson said others were "letting down" Victorians after the state fought to defeat its deadly second wave.
"As we've seen this week, it's essential every Victorian checks in when visiting a business, to help contact tracers quickly find those who could be at risk of coronavirus exposure," he said in a statement on Thursday.
The government's QR Code system will become mandatory from the end of May.
An average of 28,000 check-ins are being registered on the system every day, with more than 91,000 businesses signing up.
Meanwhile, Victoria has recorded no new local COVID-19 cases for the second day after the Melbourne man's positive test on Tuesday sparked a contact tracing blitz.
Victoria had one new overseas case on Thursday morning from 21,984 test results.
Acting Premier James Merlino said of the 115 primary contacts, 67 had tested negative and the remaining results are expected within 36 hours.
He added all the primary contacts are isolating and the progress of the case was "pretty positive so far".
The man's infection prompted returned travellers on a South Australian hotel quarantine floor being ordered into another 14 days' isolation.
Genomic sequencing testing confirmed the man became infected while staying at Adelaide's Playford Hotel.
"That's a good thing because we're not chasing unknown sources, which is always one of the biggest and one of the biggest concerns when we are doing that contact tracing. So far, so good," Mr Merlino said.
The man, from Wollert in Melbourne's outer north, tested positive after returning from India via the Maldives and Singapore on April 19 and completing 14 days' hotel quarantine.
He was staying in a room next to another person who tested positive before being moved to a medi-hotel.
SA authorities earlier barred travellers from entering the state if they had visited any of Victoria's high-risk exposure sites, with few exceptions.
It came as Victorian health colleagues scrambled to track down hundreds of fans who went to last Friday's AFL match on the same train as the infected Wollert man.
There are fears hordes may have been exposed to the virus on the Craigieburn line train while travelling to or from the Geelong-Richmond match at the MCG.
The AFL sent text message alerts to all 54,857 spectators.
Victoria has gone 76 days without a new local infection.
