Hope this helps.

http://www.gov.hk/en/residents/immig...nnel.htm#fvapc

Frequent Visitor e-Channel

You are eligible to enroll for use of the e-Channel service if you are:

Aged 18 or above;
Holding a valid travel document and where appropriate, valid multiple visit visa;
Holding one of the following documents:
HKSAR Travel Pass;
APEC Business Travel Card with ‘HKG’ printed on the reverse side;
Hong Kong International Airport Frequent Visitor Card
Frequent Flyer Programme membership card issued by airlines which have joined this scheme (please enquire with your airline).
For passengers not holding one of the documents mentioned in item 3:
Holding valid travel document which is not required to have entry visa / permit for entering HKSAR;
Have made visits to the HKSAR by air via the Hong Kong International Airport for no less than 3 times in the past 12 months immediately before enrolment for the e-Channel service
No adverse record in the HKSAR