For the common legal problems related to foreign domestic helpers, you can refer to the Immigration Department's website for details.

http://www.labour.gov.hk/eng/public/wcp/PointToNotesForEmployersOnEmployment(FDH).pdf

Some of the general law applicable to local employees also can be applied to foreign domestic helpers. Please refer to the Labor Department's website for details.

http://www.gov.hk/en/residents/employment/labour/index.htm

Labour Department

http://www.labour.gov.hk/