The rail inquiry commission now has until 26 February 2019 to complete its work.
The commission is investigating diaphragm wall and platform slab construction works at the Hung Hom Station extension on the Shatin to Central Link project. It was appointed in July and had been due to report its findings and recommendations within six months of its appointment date.
It sought an extension because of the extensive scope of the inquiry, the complexity of the matters being examined and the large number of witnesses involved.
It expects to finish all evidence and final submissions by the end of January.