The Legislative Council's welfare services panel is discussing whether the government should legislate to establish a reporting mechanism for suspected child abuse cases.
A cross-bureau working group suggested teachers, childcare workers and social workers be among seven professional groups that are required to report suspected child abuse and neglect.
People who work in a voluntary capacity or have limited time with children such as foster parents and private tutors were not intended to be included.
Lawmaker Michael Tien Puk-sun said such legislation is key to solving child abuse issues.
He asked whether vulnerable people over 16, such as mentally handicapped persons, would be protected under the new law.
In response, Law said the government is more inclined to deal with child abuse matters first. He said if the legislative range is too broad, work would be difficult and could take a long time.
Law told lawmakers he expects that drafting the legislation on mandatory reporting would take one to two years as it could involve amending professional codes.
Separately, the Law Reform Commission proposed a new offense on Friday - imposing criminal liability on people who fail to take reasonable steps to protect children under 16 or vulnerable people over 16 - including the elderly and the disabled - from death or serious harm.
Stephen Hung Wan-shun, a member of the Law Reform Commission's subcommittee, said the proposed offense targets people who purposely ignore a child's being abused and do not offer help.
Caretakers should make use of their knowledge to judge whether the injuries suffered by those they take care of are suspicious.
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.