https://www.gov.uk/government/publications/criminal-records-checks-for-overseas-applicants/countries-g-to-p-applying-for-a-criminal-records-check-for-someone-from-overseas#hong-kong
The authorities in Hong Kong have declared that Certificates of No Convictions (CNCC) can only be obtained for reasons relating to applications for a visa to visit or reside in another country, or for adoption of children. Applications for any other purpose will not be accepted.