According to The Basic Law

Section 3 The Legislature Article 73

The Legislative Council of the HKSAR shall exercise the following powers and functions; ( 8 ) To receive and handle complaints from Hong Kong residents;

Legislative Council Secretariat (Handling of Complaints)

The Legislative Council Redress System is a system operated by the Legislative Council to receive and handle complaints from members of the public who are aggrieved by Government actions or policies. It also deals with public representations on Government policies and legislation as well as other matters of public concern.

Members take turns, in groups of seven, to be on duty each week to oversee the Redress System and to receive and handle representations of and complaints made by deputations. During their duty week, they also take turns to undertake "ward duty" during which they meet with individual members of the public and provide guidance to staff on the processing of cases.