Democratic Party lawmaker Wu Chi-wai has called on the government not to amend Annex III of the Basic Law that would allow mainland immigration officers to work at the express rail link's terminus in West Kowloon.
Speaking on RTHK's Letter to Hong Kong, he said laws listed in Annex III must be confined to those relating to defence and foreign affairs.
Wu warned that if the government allows an amendment of the Annex, it would set a precedent for all types of mainland legislation to be enacted in Hong Kong.
Government officials had earlier said a joint immigration checkpoint in the West Kowloon terminus is necessary to ensure a fast and convenient service for passengers.
But Wu said separate immigration checkpoints should be set up in the West Kowloon terminus and the railway's other terminus in Guangzhou.
The railway is scheduled to go into service by the end of 2018.
http://news.rthk.hk/rthk/en/component/k2/1232016-20151227.htm