All non-essential gatherings of more than 500 people have also been banned under new powers to combat the coronavirus.
Prime Minister Scott Morrison has warned Australians to expect further restrictions and intrusions into their daily lives as the government takes further steps to try to stem the spread of the infection.
All people coming to Australia from midnight today have to self-isolate for 14 days, while cruise ships will be banned from arriving at Australian ports for an initial 30 days.
People who break the restrictions face hefty fines and even jail time.
In NSW, those who fail to comply could face up to six months in prison or a fine of up to $11,000 or both, plus additional penalties for each day the offence continues. Companies face even harsher fines.
"I urge the community to do the right thing and obey the decisions and advice of the national and NSW chief medical officers," NSW Health Minister Brad Hazzard said.
"But we will be tough if needed, to protect the wider community."
Mr Hazzard said the new powers came into force at midnight and followed a meeting of the federal government.
Schools across the country from today will adopt social distancing measures, including cancelling assemblies, excursions, and travel, as well as some events and conferences,
The provisions will also see all major sporting, arts and initiative events and activities temporarily stopped until further notice.
"We're going to have to get used some or more changes over the next six months or so," Mr Morrison said.
"There will be further intrusions, further restrictions on people's movement and their behaviour."
Australia's death toll from the coronavirus has risen to five as more travel restrictions and bans on non-essential mass gatherings come into effect.
A 90-year-old resident of the Dorothy Henderson Lodge aged care home in Sydney died on Saturday and testing confirmed she had COVID-19, NSW Health said.
A 77-year-old woman also died from coronavirus after flying from Brisbane to Sydney on Friday.
Source: 9News https://www.9news.com.au/national/coronavirus-restrictions-in-force-gatherings-of-more-than-500-people-banned/288059dc-7067-4aa6-bc3a-aba72057d956