Health officials and experts were optimistic that an outbreak of COVID-19 in the Australian state of Victoria was in decline, as the result of stricter containment measures came into effect.

On Friday, Victoria recorded 372 new virus cases and a further 14 deaths, continuing a steady pattern of decline in daily infections since peaking at 725 on August 5.

While the figure is higher than the 278 infections reported on Thursday, Australian Health Minister Greg Hunt said the apparent effectiveness of stricter testing and tracing efforts remained the cause for "cautious optimism".

"There will be up days and there will be down days. This will not be a straight-line progression."

Biostatistician and epidemiologist at the University of South Australia, Prof. Adrian Esterman told Xinhua that he was confident that Victoria's case rates would continue to decline over the coming weeks.

"The cases have definitely reached their peak and are coming down, even though there's a bit of a blip today," Esterman said.

"You get this sort of seesaw jagged pattern going up in an epidemic and we're seeing it coming down in the epidemic."

According to Esterman, modelling showed that Victoria's virus reproduction figure had dropped to 0.8 following the introduction of stage 4 social distancing restrictions and more widespread use of face masks.

With case numbers significantly lower than earlier in the crisis, the job of contact tracing was also becoming far more effective and manageable for the thousands of people assigned to the job in Victoria.

"If each infected person has got 10 contacts and you've got 200 of them, that's 2,000 people to do contact tracing with and that's an enormous task," Esterman said.

"But if you're getting 400 or 500 cases a day it's totally unmanageable. So logistically, it means that they can actually control what's happening whereas they can't with much larger numbers than that."