The government and the Hospital Authority have accused a medical staff union of spreading "unfounded" information about the contact-tracing app, LeaveHomeSafe.
They did not name any group, but the Hospital Authority Employees Alliance is urging people to boycott the app. It alleges the app's purpose is not to fight the pandemic but to spy on people.
"Only by standing together and saying no to LeaveHomeSafe we can foil the government's plot, so it can't introduce a social credit system easily in Hong Kong," the alliance wrote on its Facebook page.
It said members will be setting up street booths in various districts in the coming days as part of its campaign to persuade more people to boycott the app.
The group was also behind a strike by medical workers last February during the early days of the Covid-19 outbreak.
The Innovation and Technology Bureau said it's angry that a union group is misleading people, insisting the app doesn't have any tracking function and all the records will only be stored in the users' phones.
The Hospital Authority issued its own statement, calling on "certain medical staff" to stop spreading what it called unfounded information.
Restaurants and businesses such as gyms and cinemas have started to comply with a government order to get their customers to use the LeaveHomeSafe app before entering the premises or to leave their contact details with them.