Some opinion is that when situation not covered by SME-FRS, the CPA in charge should use his Professional skepticism and make professional judgement, which in our understanding, this opinion can also be concluded to refer to HKFRS.
In the event that the SME-FRS does not cover an event or a transaction undertaken by an entity, management may consider the SME-FRF for guidance on developing an appropriate accounting policy, consistent with the historical cost convention, for that particular event or transaction.
(Paragraph 1.2 of SME-FRS)
Example of situations not cover by SME-FRS:
Derivatives, forex and swaft, which is not cover by Section 6 Investment of SME-FRS (SME-FRS doesn't have Financial Instrument section), should be accounted using fair value model, by referring to Full GAAP.