The Hong Kong Highway Department expects work on the Central Kowloon Route Central Tunnel to start in June 2019 following publication of tender documents for the scheme.
The work to deliver the 2.8km duel three lane tunnel, 1.5km pilot tunnel and two cut and cover tunnel is expected to take 60 months to complete.
Successful bidders will also have to undertake ground investigation, drainage and geotechnical instrumentation and monitoring and slope maintenance and upgrading works.
A joint venture of Arup and Mott MacDonald has already been appointed to design and supervise the construction work.
Bids for the work are expected to be submitted by 8 March.