The first major lifting of restrictions on Melbourne is at least three weeks away.

The NSW Premier was asked about Cr Mack's timeframe of mid-to-late October to open the border at a media conference on Wednesday.

"We want to be very clear about this, and that is it's one thing to have close to zero cases when you've got restrictions in place and a lockdown in place, and another thing to see what happens once those restrictions are eased," Ms Berejiklian said.

"So we would need confidence that Victoria is able to maintain a reasonable amount of cases as their restrictions ease and it's too early to make that assessment.

"I know that our Chief Medical Officer, Dr Chant, and I are in regular communication about this issue.

"We would need to see clear demonstration that Victoria was able to manage its cases once the lockdown is no longer in place.

"That's the question we don't have the answer to."

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Albury MP Justin Clancy was ambivalent about the timeframe outlined by Cr Mack earlier this week.

"What we're hearing from the Premier's office is that mid-October, the end of the month is achievable, providing the health continuum continues to go down and I think that's critical," Cr Mack said.

Melbourne going to the third step on the Victorian roadmap to reopening - which would remove the four reasons to leave home - is dependent upon fewer than five new cases being recorded state-wide on average over the previous 14 days, and fewer than five cases with an unknown source.

The average number of cases diagnosed in the last 14 days for metropolitan Melbourne was 16.4 on Wednesday, with the total number of cases from an unknown source being 21 in the past fortnight.

Victorian Premier Daniel Andrews hoped to get below 300 active cases in Thursday's daily update.

"The strategy is absolutely working," he said.

"We didn't have the sort of opening up that some people are urging ... it's not something we can do at the moment.

"We're very close, we've got three weeks to go before we can take big steps, but the notion of opening up at 16.4 cases per day in metropolitan Melbourne is not safe, it is not steady, and it will not last."

Ms Berejiklian has repeatedly said she will not keep the border closed a day longer than needed, and in the Wednesday press conference reiterated the need for Queensland's borders to open.

"Where there are a cluster of cases in a particular location, we've demonstrated our capacity to get on top of it, whilst keeping the economy open," she said.

"And I think that should be the test that we're all put up against.

"It's one thing to have a false sense of security because you've closed your borders to everybody ... but you haven't really tested your system.

"We've maintained openness to everybody, but for overseas travellers and but for Victorians, but apart from that ... we've tried to allow as much activity as possible. I think our system has been tested."