When those plans were announced, which would have allowed, among other things, brothels, the casino, pokies venues and strip clubs to reopen, circumstances were different.

Within the space of 48 hours the ACT has closed its borders to Victorians and mandated permits and 14-day quarantine for returning Canberrans. And all of this while large parts of Australia's second-most populous state went back into lockdown.

That all this, and more, happened so quickly is a telling reminder of the sheer virulence of this disease. Even when a state or territory thinks it is travelling well, disaster can be just around the corner.

It is significant that, unlike many previous cases, the ACT's latest infections did not involve travellers returning from overseas. They are all linked to the "second wave" in Melbourne. While, as of late yesterday, no final decision on stage three had been announced, the Chief Minister said Canberrans should not get their hopes up.

"The community should expect the implementation of stage three is likely to be postponed until we have a better understanding of the Victorian outbreak and the impact on the ACT," Mr Barr said. He did say the proposal to move to a one person per two-square-metre rule, as opposed to the current four square metres, would not be implemented.

This is a sensible reaction to the Victorian outbreak, the local cases, and the emerging evidence COVID-19 has a much greater "aerosol" effect than was first thought. When a carrier coughs or sneezes the particles can linger in the air for significantly longer than the experts at the WHO originally thought.

ACT residents concerned about a possible increase in arrivals of Australians returning from abroad at Canberra Airport will also welcome the news Friday's National Cabinet meeting is to consider imposing a lower cap on the numbers that can come into the country.

This was in response to the decision to suspend international arrivals in Melbourne for at least the next two weeks. It was feared flights would be diverted to other capitals, placing additional stress on other states and territory governments.

At a press conference in Canberra, the Prime Minister did not hide his frustration with citizens who could - and in his view - should - have returned to Australia much sooner than this.

He said there was absolutely no reason state and territory governments, which have been picking up the cost of quarantine, shouldn't be charging each returnee for their food and lodging.

Within minutes NSW Premier Gladys Berejiklian said that was precisely what her government, which had spent $50 million on hotel detention as of June 17, was considering.

It is not yet known how many other states and territories will follow suit.

Meanwhile, in Victoria the epic effort to control the outbreak is being led by local health authorities, assisted by the ADF and medical professionals from other states, seems to be gaining ground.

More than one million people have been tested to date and the number of new cases recorded since Tuesday was noticeably down on the previous figure.

While these are trying times the problems can, and will, be overcome if people work together. Or, as the PM put it on Wednesday: "We're all Victorians [right] now because we're all Australians".