As Premier Daniel Andrews hit back at the prime minister, chief health officer Brett Sutton also defended the state's contact tracing following comments from federal Health Minister Greg Hunt.

Victoria had eight more deaths on Tuesday, but 55 new cases meant five-straight days under 100.

The premier said a team of officials would visit NSW later this week to look at that state's contact tracing system, which the prime minister has described as "gold standard".

Melbourne will also have five suburban response teams soon to help with contact tracing.

Asked if the NSW contact tracing system could have contained Victoria's hotel quarantine outbreak, Mr Hunt said: "Yes, that's my belief."

Professor Sutton told 3AW in response: "I wish the system were as robust then as I know it is now."

"But I can't say that it would have been stopped with a NSW system, by any means."

Victoria's "mystery" virus cases dropped by 25 on Tuesday to 4344, while active cases are also down to 1696, with no new cases in regional areas.

Meanwhile, Mr Andrews and Prime Minister Scott Morrison are at loggerheads over Victoria's controversial "roadmap" out of restrictions.

The premier vented on Tuesday after two days of Commonwealth criticism about the state plan.

On Monday, Mr Morrison said he hoped the plan to bring Melbourne and Victoria out of their lockdowns was a "worst-case scenario", with business also fiercely critical of the strategy.

"I'd say to the prime minister, the worst-case scenario is being open for three or four weeks and then closed down again. Absolutely that's the worst-case scenario," Mr Andrews said on Tuesday.

"There would be 15 minutes of happiness and then we'd be back in lockdown and arguably facing an even worse situation than we face now.

"We're grateful for the partnership that we have, but ... if I can be so bold as to have a judgment on these things, I think I've got some insight into what's happening here in our state."

The latest Victorian fatalities take the state's toll to 683 and the national figure to 770.

Victorians are now fixated on the two-week case average, which will be a key indicator for the government's roadmap out of the state's second outbreak.

As the Victorian roadmap continues to attract fierce criticism, testing numbers are causing concern.

They were down to 8704, the first time it has been under 10,000 since June 23.

While the premier acknowledged there would be fewer tests because the cold and flu season was ending, he urged anyone with symptoms to be checked.

"If you even have mild symptoms, the chances of you having this coronavirus are that much higher," he said.

Prof Sutton has said there will be no change to the September 28 roadmap milestone, when some Melbourne workplaces and schools will reopen if the 14-day case average drops below 50.

But other key dates for the potential easing of restrictions on October 26 and November 23 could be brought forward if the data is close to prescribed thresholds.

Regional Victoria, meanwhile, is on a different timetable and will be able to move to the "third step" of restrictions soon.

Australian Associated Press