Enforcement Rules of the Act Governing Relations with Hong Kong and Macau Article 15

The Residents of Hong Kong or Macau who obtained permission of residence in the Taiwan Area before the implementation date of this Act, except for those entering into Taiwan for study, may be treated as Hong Kong or Macau Residents described in Paragraph 3 of Article 4 of the Act and be allowed to accept employment to work in the Taiwan Area.
中文原文 香港澳門關係條例施行細則第15條
本條例施行前,經許可在臺灣地區居留之香港或澳門居民,除來臺就學者外,得視同本條例第四條第三項之香港或澳門居民,受聘僱在臺灣地區工作。

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