He had hoped to get to one million downloads in five days but passed the mark in under five hours, with more than two million downloads by Monday evening.

Chief Medical Officer Brendan Murphy said the uptake had been "really great".

"That is an amazing and really gratifying outcome. I am so proud of my fellow citizens," he said.

He continued to promise it was a "no risk, highly secure very safe app".

"We have a compact with the Australian public. This app will only ever be used by public health officials in the purposes of contact tracing. That is what it is for, it will never be used for any other purpose," he said.

Mr Hunt has made a declaration under the Biosecurity Act about the use of the data. The code is yet to be released.

Professor Murphy said about 7000 people had been recruited to contact tracing teams - "a huge and highly effective public health workforce".

The more Australians who downloaded the app, the more confident authorities would feel about starting to ease restrictions on movement in just over a fortnight's time.

But he said people must be prepared to change the way they interacted with each other "permanently" or at least for the foreseeable future by keeping their distance and not shaking hands.

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Asked whether there was a threshold number of new cases a day before movement restrictions would be eased, he said if numbers stayed below 20 a day with very few from unknown community transmission, "that would put us in a very strong position".

The number did not need to be zero, he said, with cabinet endorsing a strategy of "significant suppression" rather than elimination.

Testing had already been expanded to anyone with cold or flu symptoms and the next step was to start testing people with no symptoms "to try and be absolutely sure that we are catching every case that we we can".

The focus would be young adults, who were known to be transmitting the virus.

Australia has 6720 coronavirus cases, with 113 people in hospital on Monday. Forty-three people were in intensive care and 27 on ventilators. To date, 83 people have died.

The median age of people being diagnosed in Australia is 48 years, but the median age of people ending up in hospital is 61 and the median age of death from the virus is 79. While mean and women are equally represented among cases and hospitalisations, more men are dying. Of the 69 deaths at April 19, 42 were men and 27 women.

Among people admitted to hospital, 19 per cent had heart diseases, 19 per cent had diabetes, and 14 per cent had a chronic respiratory condition. Eight per cent were obese.

But among those ending up on ventilators, 30 per cent had diabetes and 26 per cent were obese. Twenty-two per cent of patients on ventilators had heart disease and seven percent had a chronic respiratory condition.

The proportion of cases needing hospitalisation in Australia is well below other countries. In Europe, 32 per cent of people diagnosed with the virus have been hospitalised. In Australia the figure is 12 per cent.

The analysis is based on cases to April 19, when there were 6606 cases.

Cough remains the main symptom by far, with 70 per cent of people with the virus reporting a cough, Just under half (48 per cent) report fever, 40 per cent sore throat and 36 per cent headache.

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