Starting November 1, all visitors to government buildings and offices – ranging from hospitals, wet markets, courts, public schools, libraries, sports grounds to police stations – must use the LeaveHomeSafe app instead of jotting down their details on paper.

Those aged under 12 or over 65, as well as disabled people who have difficulties in using the app, will be exempted from the requirement.

Speaking on a radio program on Sunday, Nip said he is aware of the difficulties faced by some citizens, such as homeless people, who don't have smartphones.

A light-handed approach will be adopted in the initial period of enforcement, he said.

For homeless people, they can leave contacts of social welfare organizations or social workers, he said.

He reminded citizens that it is illegal to provide false information or use a fake LeaveHomeSafe app.

So far Hong Kong has achieved a vaccination rate of 68.5 percent, and the city is currently going through a bottleneck in further increasing the rate as response from the elderly remains sluggish.

Nip also said that in order to get the green light from mainland authorities to reopen borders, Hong Kong must guard against imported cases, demonstrate the ability to curb local outbreaks and ensure a high vaccination rate among residents.

Experts from mainland and Hong Kong will meet again shortly to discuss the necessary criteria, he said.

Also on Sunday, Chua Hoi-wai from the Council of Social Service called upon the government to give discretion to citizens who face difficulties in using the LeaveHomeSafe app.

He also called upon authorities to work together with welfare organizations to provide affordable secondhand smartphones to grassroot citizens.