The government's controversial tracing app is now live, here's how it works.

More than two million people have downloaded the government’s COVIDSafe app in just over 24 hours, surpassing government expectations.

“Well done Australia. We’ve just passed 2m downloads for COVIDSafe,” Prime Minister Scott Morrison said on Monday evening.

“But we’ve still got more to do keep you & your family safe, protect our doctors & nurses & help us get back to the way of life we love. Join us in stopping the spread, download it now.”

The app went live on the Google Play store and iOS app store on Sunday, with registrations opening at 6pm.

As of 6am Monday, more than 1.13 million people had downloaded it, beating a target the Government didn’t expect to hit for five days in just 12 hours.

Early reactions to the contact tracing app appear largely positive, with minor complaints over bugs and glitches.

When the app first went live on Sunday afternoon its “star” ratings were middling, but now both app stores have COVIDSafe sitting on or above four stars.

Android user Paul Williamson gave the app five stars.

“This is such a great initiative and done in such a way as to make it only for one thing – keeping us safe. Please everyone install this and share it to high heaven,” he said in his review.

An Apple user going by the name darazz also gave the app five stars and said they were more concerned over the battery life from having the app running than about privacy.

“All seems good to me, other apps and websites know more about you anyway, so many other apps out there that trace you!” darazz said.

Another Apple user also recommended others to download it.

“It took less than a minute to register, very easy to do. Come on Australia, let’s beat this thing,” Apple user Priya Rosh wrote in their five-star review.

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The vast majority of ratings on the Apple store are five stars, with one star the next most popular category.

The five-star rating system often goes in this binary way.

One-star reviews on the iOS app store are mainly users complaining about technical problems with the app itself, which has been acknowledged as not working as well on iPhones as it does on Androids yet.

“Every couple of seconds the screen goes blank except says COVID safe. Makes it difficult when filling out information because it does this glitch,” Apple user slunkett said.

Others complained about not being able to pass the phone number verification step, but this bug is believed to have stemmed from registrations not opening until 6pm Sunday, while the app was available to download beforehand.

“When I tried at 6pm there were nearly 1000 negative reviews – all having their mobile rejected,” Apple user el qwerty said in a rare three-star review.

“Read the reviews and saw one that removed the number from their name to make it work. Did the same and Hallelujah – worked immediately. Why can’t that simple rule be explained at the point of entry?” the user asked.

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While you’re allowed to use a fake name on the app, you’re supposed to use your real phone number so that health authorities can contact you if you’ve been near someone later diagnosed with COVID-19.

Apple user Lynne Ellis registered concern over the phone number requirement.

“What happens if both married partners only use one telephone number? No one seems to know,” they wrote in their two-star review.

The Government has sought to dispel some of the privacy concerns by making the app only use Bluetooth and not the location services available on your phone through mobile data and GPS.

Some have said it would have been better if the Government ignored those concerns and used location tracking anyway.

“Great idea but not a huge fan of how it constantly pings with Bluetooth,” Android user Brian Chen wrote in his three-star review. “A much better solution would have been to use geo location or geofencing for those of us who don't keep Bluetooth on all the time, whereas internet is something everyone always has on, whether mobile data or wi-fi. Also don't like how I have a constant notification that I can't dismiss. Kinda annoying as someone who likes to keep my phone clean.”

Many have said the privacy concerns are a non-issue because other apps you already have on your phone collect more intrusive data.

Law-enforcement agencies and the Federal Government are supposed to be prevented from accessing the data by law, with only state and territory health authorities meant to access it.

The COVIDSafe administrator will also be able to access the app to “ensure the proper functioning, integrity and security of COVIDSafe, including to delete your registration information at your request”.

“It will be a criminal offence to use any app data in any other way. The COVIDSafe app cannot be used to enforce quarantine or isolation restrictions or any other laws,” the Department of Health’s website notes.

The department has been contacted for comment on who that administrator is, whether it’s the company behind the app or people within the department.

What law-enforcement agencies could glean from the data would likely be less useful than the data they can get under metadata retention laws, which are kept for two years rather than the three weeks the app stores data on your phone.

A recurring theme in the reviews is that everyone should download the app to save lives, slow the spread of coronavirus and protect healthcare workers, a group also invoked by the Government on multiple occasions during Sunday’s press conference.

If you’re yet to make up your mind on whether to download the app, it’s not mandatory, and it’s in fact illegal for anyone to compel you to download it.

You can make a complaint to the Office of the Australian Information Commissioner or the Australian Human Rights Commission if someone, like your employer, is pressuring you to download the app against your will.

If you download it and change your mind, you are free to delete the app.

This will delete any information on your phone; however, any information you have already agreed to share with the Government’s servers will remain until the end of the pandemic, at which point the Government has said that information will be destroyed.

If you don’t want to wait that long, there is an online form to request that your data be deleted.

Users will also be prompted to delete the app off their phones once the pandemic ends.