Is it ok to set a curfew for domestic helpers?

No, it is not ok for employers to set a curfew asking the helper to be back home at a certain time.

Hong Kong law requires that domestic helpers receive a full 24-hour period free from work. Requiring a domestic helper to be in a specific place at any time during that 24-hour period (like by setting a curfew) would mean putting restrictions on the rest day and would therefore be considered unlawful.

If you are worried about a domestic helper coming home late and waking up members of the family, have a discussion with them about this instead of enforcing a curfew. Come to an agreement that you both are okay with. Alternatively, if you are worried that late nights are affecting the domestic helper’s work, then this is a work performance issue and should be handled accordingly.