The new relaxation applies to classes with more than four people.
If all staffers inside a room are vaccinated, gym customers can be arranged into sub groups of four. A distance of at least 1.5 meters should be maintained between each sub group, or partition should be put in between them.
Before the new measure, a distance of 1.5 meters should be maintained between each participant of a training group.
In the course of training, the coach must stay at a fixed location at least 1.5 meters away from any other person in the room, while everyone must wear masks at all times.
Meanwhile, authorities will extend other social distancing measures such as the four-person cap for gatherings for another two weeks till September 29.
The extension also applies to requirements and restrictions over specified premises, including restaurants, bars and pubs, party rooms and karaoke establishments.
Countries such as Singapore and Israel have already started to administer a third jab to some citizens but Hong Kong is still conducting studies on such a move.