A lack of government trust could be the stumbling block for a new contact tracing app a Tasmanian civil liberties advocate says. The government last week announced its intention to use an app to trace close contacts of confirmed COVID-19 cases. The idea has draw criticism from privacy advocates and members of parliament who are worried about potential data breaches. Civil Liberties Australia's Tasmanian branch director Richard Griggs said the government had a huge mountain to climb to restore public trust. He said there are three types of people in society; those who will instantly reject the idea, those who will instantly adopt the idea and those who will have an open mind. On Friday, government servicesMinister Stuart Robert announced the privacy assessment of the app will be made publicly available. Mr Griggs welcomed that and said transparencywill be key if the government hopes to breed trust. "A government tracking application downloaded on your phone is a drastic step and in order for the government to be able to convince asmany people as is possible they are going to need to be very clear about how the app operates, what data is and isn't collected and guarantee it is absolutely time limited," he said. Lyons Labor MHR Brian Mitchell said the fact members of the government were publicly stating their opposition to the app showed the lack of trust. He said it should have been clearer from the start whether the app would be voluntary. "Technology can be helpful but it's important that Australians not be forced into it," he said. "That threatens to undermine community acceptance of thewider response to this pandemic." On Friday, Mr Robert and Prime Minister Scott Morrison both confirmed the app would be voluntary after some suggestions by the later that it may become mandatory if not enough people signed up. Mr Robert also confirm the app would not track people's location and all data would be stored on the users phone unless they test positive. "The app itself COVID Trace simply digitises a manual process," he said. "The app simply connects poles with another app if those two poles, so two people, are within one and a half metres for 15 minutes." Security researcher Troy Hunt, who founded the website haveibeenpwned.com, said he is cautiously optimistic about the app. He said it had a lot of potential upsides but the main concern was how they will be balanced with potential privacy risks. "I think there are a number of basic fundamentals that the app would need to achieve for myself and many others to feel comfortable with it," he said. He said having the data stored on users phones would be a good privacy control. "Hopefully the vast majority of us hopefully never contract the virus and therefore we would never have to send any identifier anonymous or otherwise," Mr Hunt said. "The joy of the [Singaporean] app is that if it is all self contained within the app and you have the ability to uninstall the app at any time."