Seafarer's Service Regulations Article 29

When anchored in a harbor known to have prevalent infectious diseases, the master shall notify all ship personnel and require them to stay onboard. All necessary control measures shall be implemented in order to prevent infection.
中文原文 船員服務規則第29條
船舶所停泊之港埠發生傳染病時,船長應通告全船,限制海員、旅客上岸,並採取各項必要防制措施,以防傳染。

English translation for reference only; the Chinese text prevails. Not legal advice.