Chan, 49, and Gordon Lam Sui-wa, 36, appeared at Kowloon City Court on Thursday to face allegations of taking part in an illegal group gathering at Hands, a bar on Tai Nan Street in Sham Shui Po, on April 2.
If convicted, they face six months in jail and a maximum fine of HK$25,000 (US$3,200) under the Prevention and Control of Disease (Prohibition on Group Gathering) Regulation, which took effect on March 29.
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Chan Wai-choi, 32, who was in charge of the bar, has also been charged in relation to the same regulation, and the Prevention and Control of Disease (Requirements and Directions) (Business and Premises) Regulation, which came into operation on March 28.
He faces one summons of knowingly allowing a prohibited group gathering, and another of failing to comply with the direction in relation to a catering business.
These directions included body temperature screening before entry, and limitations on the number of people seated together at one table, according to court documents.
But none of the three were required to enter their pleas after their lawyers asked for more time to collect documents and consult legal advice.
Prosecutors said there were no plans to press further charges against other individuals connected to the incident.
The case was adjourned by Magistrate Leung Ka-kie to December 10.
Hong Kong banned on March 29 public gatherings of more than four people, and closed pubs and bars from April 3, in a drastic escalation of social-distancing rules to check the spread of the coronavirus.
Such entertainment venues later reopened, with the latest relaxation measures allowing up to four people per table starting from Friday.
But the prohibition on group gatherings of more than four in public will continue, at least for another week, according to authorities, with the city recording more than 5,300 Covid-19 infections so far.
Tanya Chan was Civic Party vice-chairwoman and convenor of the opposition bloc before she announced last month that she would quit as a lawmaker and leave her party, citing family and health reasons.