Hong Kong's Office of the Privacy Commissioner (OPC) is highly concerned about the information leak of 20,000 people who complained about police over the past decade and will look into the case, an OPC spokeswoman said Friday.
She said the case is "very sensitive" and may breach Data Protection Principle 4, which states appropriate security measures be applied to personal data.
According to a report of South China Morning Post, a database apparently from the Independent Police Complaints Council (IPCC) revealed highly confidential records stretching back to 1996 about names, addresses and Hong Kong identity card numbers for each complainant on the internet.
It is unclear how long the list had been posted on the site, the report said.
"This information could be used for blackmail and extortion if it has fallen into wrong hands," Hong Kong Human Rights Monitor director Law Yuk-kai said.
IPCC member Lo Wing-lok said the council will investigate the privacy breach as soon as possible and take all necessary measures to stop it happening again.
A police spokesman also said the force will fully investigate whether this personal data is stored at an improper location.