at one time, a dependent of an Employment Visa holder could not work..that has been amended so that now the dep. can also work
a dependent of a Study Visa holder cannot work unless special permission has been granted by Immd.
from Immigration Department
II. Eligibility Criteria
3. For a sponsor who is a Hong Kong permanent resident or a resident who is not subject to a limit of stay (i.e. a resident with the right to land or on unconditional stay), the following dependants may apply to join him/her for residence in the HKSAR:
1. his/her spouse;
2. his/her unmarried dependent child under the age of 18; and
3. his/her parent aged 60 or above.
4. For a sponsor who has been admitted into the HKSAR to take up employment (as a professional, for investment to establish/join in business, or for training) or studies (in a full-time undergraduate or post-graduate programme in a local degree-awarding institution), or who is permitted to remain in the HKSAR as an entrant under the Capital Investment Entrant Scheme or the Quality Migrant Admission Scheme, the following dependants may apply to join him/her for residence in the HKSAR:
1. his/her spouse; and
2. his/her unmarried dependent child under the age of 18.
5. An application for admission of a dependant may be favourably considered if:
1. there is reasonable proof of a genuine relationship between the applicant and the sponsor;
2. there is no known record to the detriment of the applicant; and
3. the sponsor is able to support the dependant's living at a standard well above the subsistence level and provide him/her with suitable accommodation in the HKSAR.
i would ballpark the minimum amount at 20k per month...well above what many local families subsist on...