The only possible exceptions will be made for aid workers, essential work travel and on compassionate grounds.
Australian Border Force will determine if people are eligible to travel.
The precise timing of the ban is yet to be determined but it is expected to occur on Wednesday.
The ban, enabled by the Biosecurity Act 2015, "will help avoid travellers returning to Australia with coronavirus and the risks of spreading coronavirus to other countries", says Prime Minister Scott Morrison.
"What we've asked for advice on is the density of those cases, how many cases in a particular area that triggers actions over and above what these general rules are that apply to those areas, and that would be staged up according to the level of that outbreak and what needs to be done wherever possible to shut that down", he said.
The Prime Minister also reinforced social distancing guidelines, advising Australians should "stay at home unless it is absolutely necessary" to leave the house, which he defined as shopping for basics, exercising and going out for medical reasons.
"If you see how the virus is getting out of control around the world, if you see the huge escalation in deaths, many countries did not control the spread at this stage of the virus", Berejiklian told reporters in Sydney.
Outdoor food markets will operate at the discretion of state governments.
Personal services such as beauty therapy, tanning, waxing, nail salons, spas and tattoo parlours (but not physiotherapy) are banned.
Hairdressers and barbershops will be allowed to continue services but appointments will be restricted to a maximum of 30 minutes.
"People should not congregate together in groups, inside or outside", he said.
This reinforcement came as Victoria reached 411 COVID-19 cases, including six acquired through community transmission.
In addition to widespread business closures, Morrison announced new restrictions on funerals, which must be limited to 10 people or fewer, and weddings, which are limited to the marrying couple, celebrant and witnesses.
Funerals may only be attended by a maximum of ten people.
"The position of the national cabinet is that schools should remain open and they can provide distance learning for those parents that wish their children to remain at home", Mr Morrison said.
But some pupil-free days will be needed to plan distance learning.
Mr Morrison said the authorities would consider harsh new penalties for anyone who does not comply with a self-isolation order. Exact time for ban to start yet to be set.
The Prime Minister also announced the government will be making it offence for people to buy goods in bulk in Australia in attempt to profiteer overseas.