Treat tracing app like sunscreen: Aussie PM

Scott Morrison wants Australians to consider putting a coronavirus contact tracing app on their phones as the same as putting on suncream to protect their skin.

So far, 2.8 million people have downloaded the new COVIDSafe app, the prime minister said on Wednesday.

"I would ask for millions and millions and millions more to do the same thing," he told reporters in Canberra.

"If you want to go outside when the sun is shining, you have to put sunscreen on. This is the same thing.

"That is your ticket, Australia's ticket to a COVID-safe Australia where we can go about the things that we love doing once again."

The app uses Bluetooth to record other phones a user's mobile comes into close contact with, and stores the data temporarily so state health officials can access it if the person contracts coronavirus.

Tech experts have raised concerns the app may not work properly on iPhones unless people run it constantly without using their phone for anything else while out and about.

They have also highlighted bugs that seem to stop people registering in the app while using wifi.

Independent Tasmanian senator Jacqui Lambie is also worried the app is open to cyber-attack, saying the government already had a poor record when it came to protecting Australians' data.

Use of data and the app is protected by a biosecurity direction and will be subject to legislation when parliament returns in May, in what Mr Morrison described as a 'belt and braces' approach.

A northern Sydney business group has had to withdraw its advice to local traders to ban people who didn't have the app.

The government has said it would be illegal for businesses to screen customers for the app.

Ku-ring-gai Chamber of Commerce president Peter Vickers told AAP it shouldn't be illegal if Australia wanted to avoid a deadly New York City-style outbreak.

"If you don't want the app on your phone, by all means stay at home," he said.

His updated advice to businesses says the biosecurity determination "hardly makes use of the app a requirement and certainly does not solve the COVID-19 emergency".

"The Minister of Health thus has wimped out on his duty to protect the population," Mr Vickers wrote to business owners.

"In fact he should have ordered Apple and Android to compulsorily down load [sic] the app to all phones in Australia."

Mr Morrison said using the app was not a mandatory exercise.

"We are seeking the goodwill and support and participation of Australians to deal with the national health crisis," he said.