Australians are living under strict lockdown rules in some states but one expert says a number of rules "don't make biological sense".

"Sitting on a bench by yourself, fishing by yourself, walking on a beach if it's not crowded. Why do they matter?" Australian National University infectious diseases physician Peter Collignon told news.com.au.

"These things protect people's sanity when there are going to be restrictions for a long time."

Australians are living under strict lockdown rules in some states but the Morrison Government has flagged restrictions could be eased in four weeks, once three things are in place.

Collignon believes pubs will still be closed for a while but other activities that were low risk could be looked at.

"A lot of things we are doing are panic reactions from seeing on television what's happening in New York or London, where they have lost control of the infection, rather than doing what they are doing in Korea, which is a similar nation to us," he said.

Once "nonsensical" restrictions were lifted, Collignon believes the next step would be looking at restrictions in places like South Australia, which were less strict compared to states like Victoria.

If South Australia's restrictions are working to control the virus, then other more strict controls may not be necessary.

South Australia doesn't have a two-person limit on gatherings, and instead allows groups of up to 10 people to meet. It also doesn't force people to stay home unless they have a good reason, such as exercising.

Despite this, it has managed to get its new infections down to very low numbers, or even zero new cases on some days.

Collignon said the basic advice to keep 1.5 to 2 metres away from others, and for people to wash their hands regularly, seemed to make a lot of difference.

"We know this works and people will keep doing this intuitively over time," he said.

But others, such as allowing people to go to supermarkets but not let them go outside even if they were 2m apart, did not.

He said it was important that the rules made sense if people were expected to maintain social distancing measures for six months to two years.

"A lot of people will go stir crazy if they are locked inside their houses," he said.

"We've got to work out what to do based on a nuanced approach rather than imposing what works in a place like Bondi Beach across the entire state.