The cost is now put at HK$87.3bn; the government had originally signed an agreement with railway company MTR Corporation in 2012, when the main works of project were put at HK$70.8bn.
The Transport & Housing Bureau said the rail operator has submitted its latest cost estimate for the project, citing a number of reasons for the cost increase.
The major reasons include modification works, additional works and claims for associated delays arising from archaeological finds and preservation works at Sung Wong Toi Station. There have also been additional costs arising from a delay in site handover in Wan Chai, and works at Exhibition Centre Station to provide flexibility for topside development.
The government said that it will ask the railway company to provide detailed information and, in collaboration with its monitoring and verification consultant, will critically scrutinise the estimate.
The government will apply for additional funding from the Legislative Council upon completion of the examination and confirmation of the latest cost estimate, so the rest of the works can be completed as planned.
By the end of October, 79% of the overall works for the link had been completed. Tai Wai to Hung Hom Section and the Hung Hom to Admiralty Section of the link are expected to open in mid-2019 and in 2021, the bureau added.