"I think, as Australians go through these many months ahead, it will change many of us and our behaviours for a long time to come, and in some cases not in a necessarily bad way.''

Warning all Australians to stay home this Easter, Mr Morrison unveiled theoretical modelling on Tuesday that showed that if citizens adhered to social distancing and isolation protocols and quarantine measures remain in place, then everybody who contracted the coronavirus and needed an intensive care unit bed over coming months would get one.

Under this scenario, about 12 per cent of the population will be infected and less than 1 per cent will require hospitalisation.

If none of these protocols are followed and the virus is allowed to spread unmitigated, 89 per cent of the population will be infected and just 15 per cent of those needing an ICU bed will have one.

Future modelling

Australia's rate of infections and deaths is so low that there is not yet a sufficient database to forecast Australia-specific rates of spread and mortality rates but that will be the focus of future modelling efforts.

One of the modellers, Melbourne University professor James McCaw, said Australia could be at the peak of its infection rate.


Mr Morrison said these early gains in slowing the spread must be locked in.

"This Easter weekend will be incredibly important. Stay at home. Failure to do so this weekend would completely undo everything we have achieved so far together, and potentially worse,'' he said.

The government is operating on a basis that the nation has to learn to live with the virus because the economy needs to restart before a vaccine will be found.

This strategy involves an easing of restrictions in several months' time, all while assuming a certain proportion of the population has caught the virus and become immune, and ensuring the health system is also able to cope with serious cases.

Eradication is plausible

Chief Medical Officer Brendan Murphy said it was plausible to eradicate the virus by keeping the community locked down until the virus has run its course and infection rates were zero.

"The issue, though, is that then you don't have any immunity in the population and you really have to control your borders in a very aggressive way. And that might be for a long time,'' he said.


Mr Morrison concurred, saying the economy could not afford to be shut down for so long.

The National Cabinet has to consider the ability to actually continue to run the country under such a scenario. — Scott Morrison

The federal government has already spent more than $220 billion on stimulus, support and health measures and there simply wasn't enough money for a more prolonged shutdown.

Chief Medical Officer Brendan Murphy: "We are pursuing a path of control and suppression." Alex Ellinghausen

"The National Cabinet has to also consider the ability to actually continue to run the country under such a scenario,'' he said.

"It would involve a duration that went well beyond all of the governments' capacity to support that, then that would render such an option not workable."

Just as the states have differed in the rate and severity of the restrictions they have imposed in recent weeks, Mr Morrison said some would emerge from the crisis quicker than others.

Those who moved first would effectively be acting as a test case for others to observe but there may also be a competitive advantage in that they will attract more business activity.


"There is a very practical and pragmatic approach being followed by all states and territories, the restrictions are one of the many levers we have to pull in both terms of getting this under control, but also at a point where we can actually move forward again and start to ease them,'' Mr Morrison said.

"That's no time soon I should stress.

"It is important that we deal with this on a week by week, month by month process. Where we are in a position to make changes in the future then, of course, we will."

Mr Morrison said some states and territories "might be in a position to move when others are not''.

"Then we will learn from the experience of those states that may have trialled things," he said.

"And we may see a number of trial-type reliefs of restrictions at some point in the future and that would mean that in states like NSW or Victoria, or even south-east Queensland, that are more impacted that they be able to take this easing of restrictions with a bit more confidence."

Mr Morrison doubted NSW Premier Gladys Berejiklian's contention that the restrictions in her state may have to remain until a vaccine was found, which could be another year away.

Dr Murphy could not say what level of immunity in the community would be acceptable before restrictions could start to be lifted and he stressed the government was not pursuing a strategy of herd immunity.

"We are pursuing a path of control and suppression,'' he said.