National Security Department is responsible for:
Collecting and analysing intelligence and information concerning national security;
Planning, coordinating and enforcing measures and operations for safeguarding national security;
Investigating offences endangering national security;
Conducting counter-interference investigation and national security review;
Carrying out tasks of safeguarding national security assigned by the Committee for Safeguarding National Security of the Hong Kong Special Administrative Region; and
Performing other duties and functions necessary for the enforcement of the “National Security Law” and the “Safeguarding National Security Ordinance”.