With the exception of mail from Mainland China, postal codes are not used in Hong Kong as the Hongkong Post deems it unnecessary to adopt such a system.
Hongkong Post advised to leave the postcode field blank or try to fill in with "000", "0000", "000000" or "HKG" wherever required.
[2] As China Post does not serve Hong Kong, this code is generally not used in any other scenarios and remains little-known.
[2] Hong Kong has been a special administrative region of the People's Republic of China (PRC) since 1997.
[2] As China Post do not provide service in Hong Kong, this system is not known to most of the population.