Prime Minister Scott Morrison announced the measures on Sunday morning as part of a plan to contain the spread of coronavirus.
The measures were imposed at midnight AEDT.
Morrison said cruise ships would also be banned from arriving to Australian ports for at least 30 days.
The 14-day self-isolation does not apply to flight crews or for people travelling from Pacific Island states who transit through Australia.
“We’re going to have to get used to some more changes in the way we live our lives over the next six months or so,” Morrison said.
“There will be further intrusions, there will be further restrictions on people’s movement and their behaviour.
“But the point is, you do it in a timely way, you do it in a managed way, you do it in a careful way.
“Just because something is not necessary today, doesn’t mean it won’t be necessary in three weeks from now or three months from now.”
Victoria has declared a state of emergency after 14 new virus cases were confirmed overnight, bringing the national tally to 313 as the death toll rises to five.
Of the confirmed cases, 134 are in NSW, 71 in Victoria, 61 in Queensland, 20 in SA, 17 in WA, seven in Tasmania, one in the NT and two in the ACT.
There has been one death in WA, three in NSW and one in Queensland.
All major sporting and cultural events have been banned, while schools and universities remain open.
