The 253-kilometre section will connect the capital city of Bangkok and Nakhon Ratchasima.
Arkhom said all Thai agencies concerned have conducted the study for six times and there is still a problem over a section running past limestone mining areas in Saraburi.
The problem will be addressed only if the three mining companies agree to allow the rail line to be built past the areas, he said.
He said Thailand’s Office of the Transport and Traffic Policy and Planning has been asked to speed up talks with the three companies.
Chaiwat Thongkhamkhum, the office director, said he has negotiated with the three companies, particularly over compensation for land expropriation.
An agreement is expected to be reached this month so that the construction of the 3.5-kilometre section between Klang Dong and Pang Asok stations can start in November.
The next stage is to extend the track to Nong Khai on the border with Laos to southern China.
The project is part of China's huge regional infrastructure plan to build a high-speed rail network connecting its southern city of Kunming with Laos, Thailand, Malaysia and Singapore.
In mid July, the Thai Government approved an investment worth 5.2 billion USD to build the Thailand-China high-speed railway. BY VIETNAMPLUS.