
"I am willing to bare all the facts for scrutiny," he said.
Sophon said he was prepared to rectify the project if critics could point out flaws.
Bus leasing is the practical solution for Bangkok Mass Transit Authority which requires a Bt6 billion government subsidy per year and is in dire need of improvement to its services, he said.
The leasing charges might appear high, but are reasonable because the BMTA could enlarge its bus fleet without having to shoulder the investment outlay, he said.
"By bringing 4.000 new buses into service, it is possible to improve on the transport network in the capital, enabling commuters to pay about Bt30 per day to and from their work place, regardless of the number of connections made," he said.
He said his ministry is about to complete the drafting of the terms of reference for the leasing contract.
The minister added that he is open to constructive suggestions from the coalition and opposition lawmakers in order to ensure favourable contractual provisions for the lease.
In a related development, senators under the Group of 40 faction issued a statement criticising the bus leasing as unjustified.
The statement outlined a six-point rebuttal and urged Sophon to review the project.
Firstly, it said authorities should assign a priority to lease the locally-assembled buses instead of looking for a foreign supplier.
Secondly, the leasing should be divided in batches rather than seal a single deal for 4,000 buses.
Thirdly, the calculation for leasing charges should be revised to base on a periodic count for each bus in operation rather than a lump-sum payment.
Fourthly, the buses should be reconfigured to serve the handicapped.
Fifthly, the contractual specifications should not be designed to favour a particular supplier.
Sixthly, the prospective buses for leasing appear to lack the environmental-friendly technology.
Senator Kechasak Somboon said the government might cut down the project cost from Bt74 billtion to Bt43 billion after revising the contractual terms.