The median age of Australians diagnosed with novel coronavirus has been revealed to be 48 years old.

There are now 3,400 cases of the virus in Australia, a vast majority of which have been diagnosed in New South Wales and Victoria.

Addressing the media on Saturday afternoon, Deputy Chief Medical Officer Dr Paul Kelly said there was a wide range of ages.

“The oldest person is 98 and we have had a couple of small babies but have also developed this disease,” he said.

The cruise ship Carnival Spirit docks at Port Kembla in Wollongong, Saturday, March 28, 2020. The Federal Government yesterday announced that any international travellers arriving in Australia will be quarantined in a hotel for 14 days before being allowed to return home. (AAP Image/Dean Lewins) NO ARCHIVING Credit: DEAN LEWINS / AAPIMAGE

Of the infections, two-thirds were contracted overseas.

Kelly said that figure proved why the new restrictions on international arrivals were necessary.

Almost 500 cases have been reported in people who have recently arrived in Australia on a cruise ship.

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From midnight on Saturday, Australians arriving from overseas will be quarantined in state-supplied hotels or facilities for 14 days.

It had previously been a self-isolation period of 14 days in the arrivals’ own homes - but that has since been changed since people would breach the quarantine period.

“The force of law will be there to stop people leaving that hotel and there will be fines, even imprisonment, depending on the state or territory where that arrival takes place,” Kelly said.

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During the press conference, Kelly also addressed the median age of the deaths as a result of the virus.

On Saturday, a 91-year-old woman from New South Wales was announced as the country’s 14th death.

The average age, however, of fatalities is 77.

Kelly says this is largely because there have been some younger deaths, including a 68-year-old.