An essential part of the government's strategy to combat COVID-19 is identifying and isolating as quickly as possible people who have been exposed to the virtus. Currently this is done by getting infected people to recount their movements and who they might have been in contact with over the previous 14 days. The app will greatly enhance the speed of contact tracing and reduce reliance on people's recollections.

The app uses the Bluetooth function on smart phones to detect other phones nearby that also have the app installed. If you are within 1.5 metres of someone for more than 15 minutes who also has the app installed the apps will swap and store details.

The app collects and stores four pieces of information: your name, mobile phone number, age and postcode. This is the information that is transmitted to the app on other phones if you are within 1.5 metres for 15 minutes or more.

Several government MPs including former Nationals leader Barnaby Joyce have indicated they will not download the app because of concerns it could be used to track their movements. But Government Services minister Stuart Robert says no geolocation information is collected. "Health doesn't care where people are on the face of the earth. It's only about how they trace," the minister says.

The information is stored in encrypted form on the app on your phone. It is transmitted to a national health data store only if you, or someone you have been within 1.5 metres of for 15 minutes or more, tests positive for COVID-19.

It is sent from the national health data store to health officials in your state or territory (as determined by your postcode). These officials use the information to contact you in order to organise a test.

Only state health officials involved in contact tracing for COVID-19 infections will have access to the data, and only in the event that you, or someone you have had close contact with, are infected.

The app on your phone stores data for 21 days before it is deleted. All the data is destroyed if the app is deleted.

All information held in the national health data store will be destroyed at the end of the pandemic, Mr Robert says.

All data held either on the app or in the national health data store is encrypted.

A privacy impact assessment of the app is being prepared with guidance and advice from the Office of the Australian Information Commissioner and is expected to be released later this week.

The Law Council of Australia says a comprehensive privacy impact statement is vital to ensuring people are able to exercise informed consent in downloading and using the app.

The government has also undertaken to publicly release the app's source code.

Mr Robert says the Australian Signals Directorate and the Australian Cyber Security Centre have both been consulted on app security measures.

Cyber security experts warn of the risk that the system could be hacked and have urged the government to consider the advice of outside experts on how to improve data security.

No. Installing the app is voluntary, though Prime Minister Scott Morrison says it is his "very strong preference" that people do so. At this stage the government has not indicated plans to compel people to use the app.

Mr Robert says even if only 1 per cent of people install the app, that will be an improvement on where we are now. The government says that expanded testing, improved contact tracing and an ability to rapidly identify and shutdown outbreaks are vital to begin easing current restrictions. Mr Robert says the more the app is adopted, the better the prospects for controls to be lifted.

The government has indicated the app will be released within the next two weeks.

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