Professor Brendan Murphy on Sunday said the number of new COVID-19 cases was the lowest in days and there was continuing evidence that the growth in infections was "flattening".

The government medical adviser said there were 5687 coronavirus cases nationally, a rise of 139 in the last 24 hours.

"That is probably the lowest rise we've had for a few days and it does tend to continue the trend we've seen of flattening of the curve," he said.

The chief medical officer said Australia was "in a good place at the moment" as it tried to limit the spread of COVID-19.

"We are achieving good control because the community has done what we have asked," Professor Murphy said.

"They have done all of the things in the main that we've asked from them over the last weeks and it's been hard."

However in 10 per cent of cases there was no known contact with another case, a figure worrying health professionals desperate to prevent a rise in community transmissions.

Professor Murphy said Australians had adapted well to COVID-19 social distancing restrictions aiming to limit the virus spreading and preventing hospitals from being overwhelmed in ways seen overseas.

He was confident if people adhered to restrictions, Australia could prevent the situations unfolding overseas such as in New York, where infections are surging.

"That's because we got on top of the early outbreaks and because we've introduced measures recently to control the borders, to control those people coming into the country and more recently to control the community transmission," Professor Murphy said.

Australia had social distancing restrictions similar to countries with much larger outbreaks of COVID-19, he said.

"We're at a pretty significant phase of restrictions at the moment."

Thirty four people have died in Australia from the coronavirus and 91 people are in hospital intensive care units, 33 of them on ventilators.

More than 2000 people have recovered from the virus nationally.

Asked about testing people without symptoms, Professor Murphy said the only situation where it might be valuable at the moment was in an aged care outbreak because the government had found some aged care residents can have asymptomatic infections.

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