A nationwide crackdown on social gatherings will be expanded in a bid to slow the spread of coronavirus.

Key points: The Prime Minister announced a list of additional activities now restricted to slow the spread of coronavirus

The Prime Minister announced a list of additional activities now restricted to slow the spread of coronavirus Shopping centres will continue to operate, but group events such as weddings and funerals are limited to small number of participants

Shopping centres will continue to operate, but group events such as weddings and funerals are limited to small number of participants With some exceptions, Australians are now banned from travelling overseas

Prime Minister Scott Morrison announced the new restrictions late on Tuesday following a National Cabinet conference call with state and territory leaders.

He said the changes were necessary to functions identified as "major transmitting events".

From midnight on Wednesday, these activities and businesses will no longer be allowed to continue:

Amusement parks and arcades

Amusement parks and arcades Indoor and outdoor play centres

Indoor and outdoor play centres Community and recreation centres, health clubs, fitness centres, yoga, barre, spin facilities, saunas, wellness centres

Community and recreation centres, health clubs, fitness centres, yoga, barre, spin facilities, saunas, wellness centres Public swimming pools

Public swimming pools Galleries, museums, national institutions, historic sites, libraries, community centres

Galleries, museums, national institutions, historic sites, libraries, community centres Auction houses

Auction houses Real estate auctions and open house inspections

Real estate auctions and open house inspections In-store beauty therapy, tanning, waxing, nail salons and tattoo parlours, spa and massage parlours (excluding allied-health-related services, like physiotherapy)

In-store beauty therapy, tanning, waxing, nail salons and tattoo parlours, spa and massage parlours (excluding allied-health-related services, like physiotherapy) Food courts within shopping centres will only be able to sell takeaway. Shopping centres themselves will remain open

Mr Morrison also addressed specifics around a number of other activities:

Hairdressers and barber shops can continue, but a customer must not be on the premises longer than 30 minutes

Hairdressers and barber shops can continue, but a customer must not be on the premises longer than 30 minutes Personal training and boot camps are limited to a maximum of 10 people

Personal training and boot camps are limited to a maximum of 10 people Weddings can continue, but only with the couple, the celebrant, and witnesses totalling a maximum of five people

Weddings can continue, but only with the couple, the celebrant, and witnesses totalling a maximum of five people Funerals are limited to a maximum of 10 people

Funerals are limited to a maximum of 10 people Outdoor and indoor food markets will be addressed by individual states and territories

The Federal Government is ramping up efforts to remind people of how they can help slow the spread of coronavirus. ( ABC News: Joel Zander )

On Wednesday morning Australians began receiving text messages from the Government urging them to observe physical-distancing guidelines.

Mr Morrison said visits to homes, even with family, "should be kept to a minimum and with very small numbers of guests".

"We don't want to be overly specific about that; we want Australians to exercise their common sense," Mr Morrison said.

"Going out for the basics, going out for exercise, perhaps with your partner or family members provided it's a small group — that's fine.

"Barbecues of lots of friends or even extended family coming together to celebrate one-year-old birthday parties and all these sorts of things — we can't do those things now.

"If you're gathering together in a group, say 10 people, outside together in a group, that's not ok."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 23 seconds 1 m 23 s Mr Morrison said private gatherings in homes should be kept to "very small numbers of guests".

The Prime Minister said the states and territories were considering whether to make it an offence to a host a house party.

"You should only go outside your home to go to those essential things I talked about, not to go and congregate in groups," Mr Morrison said.

"If we do all these things then we are going to be able to put greater pressure on slowing the rate of the spread of this virus."

The Prime Minister also announced Australians would be banned from travelling overseas.

He said the number of people travelling overseas was very low but there were some people who continued to defy the "do not travel" warning issued by the Department of Foreign Affairs and Trade.

He said the warning would "turn into a ban" that came into force on Wednesday.

"No-one should be getting on a plane and going overseas," Mr Morrison said.

"We have been making the point for some time."

However, he did say exceptions would be made for aid workers and for compassionate, work-related and other essential travel.

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Australia's Chief Medical Officer Brendan Murphy has demanded recent travellers stay in self-isolation. ( AAP: Lukas Coch )

Chief medical officer Brendan Murphy, who also addressed the conference, said the measures were draconian, but necessary.

He emphasised the importance of people staying quarantined in their homes if they had returned from international travel or had been in contact with someone who came down with the disease.

"If we're going to control community transmission we have to stop the capacity of this virus from spreading from person to person," he said.

"It is a long haul and that is why we are keen to keep society functioning but keep society safe."

When the National Cabinet last convened on Sunday it agreed to implement stage-one restrictions, forcing the shutdown of venues including clubs, pubs, sporting venues and places of worship.