All states and territories can now access data from the COVIDSafe app to trace people who may have been exposed to the coronavirus after privacy rules were finalised, Deputy Chief Medical Officer Paul Kelly has confirmed.
More than 5.6 million people have now downloaded the app, which records close contacts through the phone's Bluetooth system.
It was intended to help speed up the process of contract tracing, and is a cornerstone of the strategy to reopen the country after widespread restrictions.
However states and territories were unable to access the data until privacy rules were finalised.
This was despite millions of people having already downloaded the app.
Professor Kelly said on Wednesday all states and territories had now signed up to be able to use the data.
"I can announce the app is fully functional," Professor Kelly said.
"All states and territories have now been trained to use it and know what information they are going to get and how it can be used for contact tracing purposes.
"We are now absolutely certain privacy and data security issues, that's all taken care of, in terms of states and territories agreeing to our proposals.
"We will look forward to seeing how that help our disease detectives do their work in coming days."
Professor Kelly was not aware of any jurisdictions using the data yet but said," I am looking forward to hearing from colleagues how useful it is".
There have been nearly 7000 cases of coronavirus in Australia, with more than 6200 people recovered and 97 deaths.
Chief Medical Officer Brendan Murphy said it was likely that around 20 million people worldwide had been infected by COVID-19, almost five times the number of cases reported by the World Health Organisation.
Professor Murphy said the coronavirus mortality rate rate in countries like Australia where there was extensive testing appeared to be between 1 and 2 per cent.
He said it was likely that countries with higher death rates had many undetected cases.
"I would be very surprised if the true international case load is not closer to the 20 million mark. There are countries that don't really have access to testing where there are outbreaks," Professor Murphy told a parliamentary inquiry.
The nation's top public health expert said that international travel remained a remote prospect, warning of the risk of significant outbreaks in regions so far largely untouched by the virus including Africa and the Western Pacific.
"I have no vision, in the current international scene, where international border measures of some strong rigour won't be necessary," he said.
"Border measures will be one of the last things to go."
He said places like Africa were still in the early stages of the pandemic and their relatively weak health systems made them vulnerable.
"The potential for very significant problems in those countries without a strong health system is great; Africa is certainly one of those areas," he said.
"We are in a good position but only will we be able to maintain that by keeping strong border measures.
"The world situation will evolve over many months."
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