The Hong Kong Highways Department is mulling plans to build a 4km long tunnel, costing $640M, as part of a 6km north-south highway on Lantau Island.
This follows the rejection of original plans for the expressway by the Environmental Protection Department (EPD) which proposed construction partly at-grade and partly on viaduct.
Mouchel Asia studied more than 17 alternative routes and design options before recommending the alignment that was rejected.
Highways Department insiders confirmed that a new feasibility study, put out to competitive bid, would be carried out to fully assess the tunnel option which is likely to be triple the cost of the initial scheme.
"We have got to write a brief with EPD for a new environmental impact assessment. Together we will look at a number of options before inviting consultants to submit expressions of interest for the tunnel feasibility study," said one highways official.
Among the issues that have to be considered is whether the tunnel should be a dual two- or three-lane carriageway.
The source gave no timetable for inviting tenders for the consultancy but expected invitations to be issued by next summer.
Rejecting the environmental impact assessment into the original scheme, EPD director Robert Law said the project between Mui Wo and Tai Ho Wan is "likely to be prejudicial to the health and well-being of the flora, fauna and eco-systems" in the area.
