These were the government's proposals on labelling (the full document is here):
c) Requirements on Labelling Format
12. There is no standard format for expression of energy and nutrient value in the food labels among different jurisdictions (see Annex 1). For some countries, energy value could be expressed in kilocalorie and for others, in kilojoule. Likewise for nutrient value, some countries allow the labelling in per 100 g/ml format while others require the labelling in per serving format. Some countries further require the labelling of energy and/or nutrients in both formats and some allow flexibility for the food traders to choose either one.
13. We see merits in the different approaches. For labelling of energy value, while kilocalorie is more commonly understood or used by Hong Kong people, kilojoule is the International System of Units (SI units) of energy. For labelling of nutrients, labelling in per 100 g/ml will facilitate comparison by consumers but labelling in per serving format is more easily understood by laymen.
14. Since different labelling methods are adopted by different jurisdictions and stipulating a rigid format will necessitate re-labelling of the food products of certain countries (even though the information on core nutrients are all there in the packages and are true and accurate), we consider that we should allow flexibility in this area. We therefore propose to allow the labelling of energy in either kilocalorie or kilojoule format and the labelling of nutrients in either per 100 g/ml or per serving format.