Non-essential indoor gatherings of more than 100 people have been banned by the Federal Government as the country responds to the coronavirus pandemic.

Prime Minister Scott Morrison also warned Australians not to leave the country as the disease spreads, saying: "We haven't seen this sort of thing in Australia since the end of the First World War."

The Prime Minister announced measures in the following areas:

Aged care: Residents of aged care homes will only be able to have one visit per day, of no more than two people

Aged care: Residents of aged care homes will only be able to have one visit per day, of no more than two people Gatherings: Indoor gatherings of more than 100 people are banned, with exceptions

Gatherings: Indoor gatherings of more than 100 people are banned, with exceptions Social distancing: A renewed call for Australians to stay 1.5 metres away from others

Social distancing: A renewed call for Australians to stay 1.5 metres away from others Shopping: A plea to end "un-Australian" panic buying

Shopping: A plea to end "un-Australian" panic buying Schools: To remain open, for now

Schools: To remain open, for now Travel: The Government recommends abandoning international travel

"This is a once-in-a-100-year-type event," Mr Morrison said.

"Life is changing in Australia, as it is changing all around the world. Life is going to continue to change.

"The travel advice to every Australian is do not travel abroad. Do not go overseas."

The new restrictions were agreed to during a phone hook-up with federal, state and territory leaders last night.

A human biosecurity emergency has been declared, giving the Federal Government extra powers to respond to the crisis

Work restrictions on 20,000 student nurses have been lifted, so that they can help with the health response.

Aged care

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 3 minutes 5 seconds 3 m 5 s Aged care facilities to place tough restrictions on visitors

Anyone who has been overseas or in contact with a confirmed case of COVID-19 within a fortnight will be banned from visiting aged care homes.

Aged care residents will only be able to receive one visit a day, with a maximum of two people visiting.

"This could be very difficult for families," Mr Morrison acknowledged.

No school groups will be allowed to visit, and children under 17 are advised to visit "only by exception".

Gatherings

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 2 minutes 9 seconds 2 m 9 s Non-essential indoor gatherings of more than 100 people banned

While imposing the 100-person indoor restriction, the Government is also considering further restrictions on crowded indoor environments.

Schools, universities, airports, public transport, medical and emergency services facilities, aged care homes, jails, courts, parliaments, supermarkets and many workplaces are exempt.

The Prime Minister said religious gatherings must comply with the new measures.

The pre-existing ban restricting mass outdoor gatherings to 500 people will remain in place.

Social distancing

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 39 seconds 39 s Work restrictions on 20,000 student nurses have been lifted

Chief medical officer Brendan Murphy urged Australians to continue social distancing and keep at least 1.5 metres apart.

"No more hand-shaking, no more hugging, except in your family," Dr Murphy said.

"You can do that in your family because you're already close to your family.

"No more scant attention to hand hygiene. Wash your hands all the time. Use hand sanitiser and just practice sensible practices."

Shopping

Mr Morrison also pleaded with Australians to stop panic buying and hoarding, which has stripped supermarkets of supplies.

"I can't be more blunt about it. Stop it," he said.

The Prime Minister said there were no supply shortages and that health experts had advised the Government there was no need for "bulk purchases".

"There is no reason for people to be hoarding supplies in fear of a lockdown or anything like this," he said.

The Government's advice is for people to have a few days' worth of supplies. They have been urged to return to regular shopping habits to give supermarkets a chance to restock their shelves.

Schools

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 2 minutes 36 seconds 2 m 36 s Australia's Chief Health Officer Dr Brendan Murphy explains why the government is keeping schools open

Mr Morrison said health officials had advised federal and state governments to keep schools open.

"We all love our kids and there is nothing we wouldn't do for them," he said.

"I am telling you that, as a father, I'm happy for my kids to go to school."

But he said state governments had the power to close schools on a case-by-case basis if there was an outbreak.

Mr Morrison said if a school was to close today, it would likely not reopen until September at the earliest.

"That means the disruption that would occur from the closure of schools around this country, make no mistake, would be severe."

Travel

The Prime Minister declared air travel itself was low-risk, but said the movement of people from place to place was a problem.

The Government hopes travel restrictions will reduce the number of cases of the virus imported into the country.

However, travel bans and a fall in tourist numbers are having a major economic impact.

Mr Morrison said the aviation sector had been the "hardest hit" and on Wednesday morning the Government announced measures to support airlines.

Some parts of the country with vulnerable residents, such as remote Indigenous communities, will be restricted to visitors. A list of sites is currently being prepared by states and territories.

Public transport and ridesharing services remain operating, but social distancing is recommended.