Postcode 3029, which include suburbs north of Werribee including Hoppers Crossing and Tarneit, has 150 active cases and five more infections in the past 24 hours. Yet some parts of the Mornington Peninsula and the city's northeast have seen few new infections and have active case numbers more similar to regional Victoria.

Before the whole of Melbourne went into stage 4 lockdowns, scores of suburbs with high rates of new cases were declared "hotspots" and had stay-at-home restrictions imposed.

These restrictions meant people could only leave home to go to work or school, to care for someone, for daily exercise and essential shopping.

However, ring-fencing suburbs would go much further, effectively keeping them under stage 4 restrictions until numbers in that area reduced below a certain level.

It's an idea that McLaws has advocated for some time, pointing to China where outbreaks are fiercely jumped on.

"China put in place the ring-fencing of cities, but have then instigated ring-fencing in hotspots within cities, and the success of that emboldens my idea that this could be the way to go," she told the ABC in June.

McLaws said it worked, but conceded: "It's not pleasant."

LOCAL LOCKDOWNS

While Chinese authorities locked down the entire city of Wuhan, as well as other centres, early on in the pandemic, more recently it has taken to restricting movements in suburbs rather than citywide.

When numbers rose in Beijing in June, 21 residential communities close to produce markets were closed off rather than the entire city.

However in Urumqi, in China's restive western province of Xinjiang, much of the city has been in a strict level of restrictions since mid-July, despite low cases in recent days.

Some residents have reportedly taken to shouting in unison from their unit balconies in frustration.

The UK has gone from national restrictions to a strategy of more localised lockdowns.

The cities of Leicester and Aberdeen have been placed in – and emerged from – local lockdowns.

These lockdowns can vary across cities. In Manchester, for instance, on the same day that the local government area of Oldham, in the city's northeast, went into restrictions, Wigan – just 50km away – had its restrictions eased.

The UK restrictions would likely fall short of the Melbourne "ring-fencing" proposal.

In Oldham, residents can still go to work and school and even eat out but gathering numbers are limited.

However, in Aberdeen and Leicester, pubs and restaurants closed and people were not allowed to travel further than 8km from home.

England has three definitions for places where cases are on the up – these are areas of concern, areas of enhanced support, and areas of intervention. Only the latter involves major community-wide restrictions.

PRESSURE FOR EXIT STRATEGY

On Monday, Victorian Premier Daniel Andrews said he "can't rule out" stage 4 restrictions still being in place for Melbourne beyond the September 13 end date.

"It is very difficult to know what those settings will be. They have to be guided by the data, the science and the very best medical advice."

He said the state would lay out a plan on Sunday to ease the lockdown.

"What we need to hear from Daniel Andrews is, what is the appropriate level of new cases in Victoria for him to open up stage 4 restrictions?" said Treasurer Josh Frydenburg.

"It's only two weeks to go,'' he told ABC News Breakfast on Monday.

"The mental health impacts are immense. I mean, kids are not seeing their friends. Grandparents are not seeing their grandchildren. Families can't go to work. Businesses have their doors closed. We're subject to curfews in Victoria. You can't move more than 5km from your home. The damage is immense. Yet, the Premier has not provided a road map out."

However, when challenged by host Michael Rowland to provide his own assessment of an "acceptable level" of daily cases, Frydenberg also failed to provide a number.