Please note Nationals of Sri Lanka traveling on Cathay Pacific (CX) to Hong Kong SAR are allowed to transit without a visa if passenger has a valid visa or proof of residency of Australia, Canada, Japan, Korea (Rep.), New Zealand, United Kingdom, USA or a Schengen Member State. They must transit within maximum of 12 hours.
WARNING: Passengers must arrive and depart Hong Kong on Cathay Pacific Airways operated flights only and a HKG Transit Visa is required when connecting with an airline other than Cathay Pacific (CX)’’
Please refer to TIMATIC and IATA Travel Centre:
IATA travel Centre link
https://www.iatatravelcentre.com/passport-visa-health-travel-document-requirements.htm