NSW has experienced an increase in cases where there is no link to an existing case, referred to as community transmission and on Friday morning NSW Premier Gladys Berejkilian said further measures may be necessary to stop the spread.

Victorian Premier Daniel Andrews said stage three "would come" in that state, but wouldn't elaborate on what that meant, or what would trigger it coming into force.

"It is not yet here but when it is, I will take you through from A to Z what all that actually means and that proportionate response, that localised responses exactly the way we should be going," he said.

Ms Berejiklian said that essential businesses like supermarkets and pharmacies would stay open, and people would be given enough warning.

"Please know that no matter what decisions our state takes in the coming days and weeks, that you will always have a supermarket you can get what you need from. You will always have a pharmacy," she said.

"You will always have the essential things that you need to use for your daily health. Please know that is never in question. There is no need to panic. There is no need to hoard. Those essential things will always be available."

The decision to move ahead with the restrictions would be based on factors like community transmission, hospital capacity and whether people are heeding existing messages to stay home.

ACT Chief Minister Andrew Barr has also made assurances that supermarkets will remain open, as well as making it clear the territory is likely to move in line with NSW.

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Despite calls from some medical professionals for Australia to move to a "lockdown" similar to that seen in other countries, Prime Minister Scott Morrison said on Friday that no leaders in Australia were using that term, and warned media against using it in case it caused panic.

"What I would flag is going forward, the states and territories are getting in different phases of where the virus is at, and that you may see in the future, greater variation in how far restrictions go in some parts of the country, versus others," he said.

Mr Morrison said they were looking for flexibility in future measures, and was forceful in his wish to keep people in work.

Countries like the United Kingdom and New Zealand have introduced more restrictive rules on people's movements, giving some insight into what future stages in Australia could look like.

New Zealand started a four week shutdown on Wednesday, where all non-essential businesses were told to close, all events and gatherings were cancelled and schools were also closed. Workplaces were told their employees had to work from home if they were able to. Domestic travel was also banned and public transport was only to be used for people undertaking essential services.

In the United Kingdom a police enforced-lockdown has been introduced, with people only allowed to leave the house for shopping for necessities, one form of exercise a day, medical needs, caring needs or to go to work when absolutely necessary.

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