The app, which he said would be downloaded by Australians voluntarily, would enable the information about their movements to be "uploaded immediately to the public health unit", whereas the manual tracing process could take days. The push came as the number of Australians to have contracted the coronavirus hit more than 6500 and the death toll to rose to 65. Loading Replay Replay video Play video Play video Professor Kelly said Australia "continues to do well" when contrasted with the "mind-boggling" global tally of more than two million cases and 143,000 deaths, but that vigilance was needed - especially if citizens wanted to regain some aspects of their former lifestyles. Mr Morrison said in a radio interview on Friday morning that for the tracing app to be effective, 40 per cent of Australians would need to download it - double the share that used a similar app in Singapore.

He would not rule out making it compulsory for all Australians to download the app - and carry the phone at all times - if sufficient voluntary take-up was not achieved. Loading "My preference is not to do that; my preference is to give Australians a go at getting it right," Mr Morrison said. "That's my objective, that's my plan A, and I really want plan A to work." He called on Australians to support the initiative "as a matter of national service" akin to buying war bonds, saying that while many would ordinarily never download such an app, "this is not an ordinary time".

"If you download this app, you will help save someone's life," Mr Morrison said. He said the app would not be used to prosecute people who had breached isolation or quarantine requirements. Professor Kelly said authorities would "start with voluntary and we'll see how we go." "I've always been a believer in the Australian people making the right decision so I think the voluntary approach at first is the way to go," he said. "We have work to do to make sure this is good and safe and cover off privacy concerns."

Asked about the controversy in Tasmania over a healthcare worker accused by Prime Minister Scott Morrison of lying to contact tracers investigating the outbreak in the state's north-west Tasmania - a claim that has been hosed down by state authorities - Professor Kelly said: "I will definitely at this point encourage people to be honest and help with contact tracing." "It is a crucial way we can get to the bottom of what happens and to prevent others from developing illness and crucially, and this has happened as well again in north-west Tasmania, to make sure we are protecting the most vulnerable people in the community, including those in residential aged care," he said. Professor Kelly said authorities would be carefully considering which sectors to lift restrictions in over the next month, after Prime Minister Scott Morrison's suggested the retail industry could be reopened for business. "I think a gradual reintroduction of as much as we can get to normal life in Australia would be most welcome," he said.