Responsible for the office of the Chief Secretary for Administration. The Chief Secretary for Administration is an official member of the Executive Council and the highest official among the three Secretaries who can act as the Chief Executive.
The functions and powers of the Chief Secretary for Administration originated from the assistant secretaries in the colonial era of Hong Kong. 1976, renamed Chief Secretary, is the head of the Hong Kong government, the chief civil servant of Hong Kong, and an ex officio member of the Executive Council and the Legislative Council. She is in charge of the Secretariat (renamed the government headquarters after the return of Hong Kong) and all government civil servants, and carries out the instructions of the Governor.
Before June 2002, the Chief Secretary for Administration was a civil servant, the highest position among civil servants, and the director was subordinate to them and politically and administratively superior to them. However, after the former Chief Executive Tung Chee-hwa (1997-2005) implemented the accountability system for senior officials, the Chief Secretary for Administration became a politically appointed official, and all directors were directly responsible to the Chief Executive.
The Chief Secretary for Administration and the Secretary for Administration have become colleagues, and the power and functions of the Chief Secretary for Administration have been weakened. She is only responsible for the work designated by the Chief Executive, and there is no fixed scope. Without the order of the Chief Executive, she can't interfere with various Policy Bureaux. She is just higher in rank and salary than the director, and is dubbed as having no real power.
References:
Baidu Encyclopedia-Chief Secretary for Administration of Hong Kong Special Administrative Region