Privacy campaigners have demanded a thorough review of the system for handling complaints against police, after personal details of complainants were found on the internet this month.
They say the two bodies that handle complaints could be combined into one, similar to the Independent Commission Against Corruption.
The call was made as about two dozen members of the Concern Group on Privacy demonstrated outside police headquarters.
The protesters included veteran activists 'Long Hair' Leung Kwok-hung, Lui Yuk-lin and Lau Shan-ching, who were among 20,000 people whose names, addresses, identification numbers and other details were made public in the internet blunder.
An IT contractor, EDPS Systems, was later blamed for the leak.
The group demanded the government conduct a thorough review of the functions of the Complaints Against Police Office, which investigates complaints, and the Independent Police Complaints Council (IPCC), which reviews its decisions.
