A respiratory medicine specialist, Leung Chi-chiu, said on Tuesday that now is a good time for Hong Kong to further relax social distancing measures, including use of the LeaveHomeSafe app and the limit on public gatherings.

From October 6, the government will allow up to 12 people to sit together at a restaurant instead of a maximum of eight, while the number of people able to attend a banquet will be doubled to 240.

Leung said on an RTHK programme that he thinks these relaxations won't carry much risk because the local population has basically achieved herd immunity against Covid.

He said more measures can now be relaxed, starting off with those that affect the economy and people's livelihoods.

For example, he said, the LeaveHomeSafe app should be abandoned because the vaccine pass scheme can be used to trace contacts of infected people.

"What we need to know about the LeaveHomeSafe app, it's not just for scheduled premises, you need to use it in many places but people actually don't use it. It's not used to track [infected people] at supermarkets, shopping malls and other scheduled premises," the doctor said.

"Many people go to these large structures, they go in different parts of them, it's hard to tell if people inside had contact with each other."

He also said the ban on public gatherings of more than four people should be scrapped, arguing that there are often crowds in places like shopping malls and supermarkets anyway.

Leung said the requirement for people to wear masks outdoors could be relaxed, but it should be kept for indoor places this winter.

He also suggested that the amber health code for inbound travellers can now be dropped and that after one PCR test at the airport, arrivals could use rapid antigen tests to check their Covid status over the following days.