Pham Huu Son, a spokesperson for the TEDI-TRICC-TEDISOUTH consortium said the Ministry of Planning and Investment's (MPI) estimate of $26 billion for the North-South high-speed raiway project "has no basis."

The MPI's price tag is much lower than the $58.7 billion proposed earlier by the Ministry of Transport (MoT) because of lower speeds at which trains will run and "a more optimized route." The train speed under the MPI’s proposal is 200 kilometers an hour, lower than the 350 kilometers proposed by the MoT.

The TEDI-TRICC-TEDISOUTH, comprising three Vietnamese construction firms, has been hired by the MoT as a consultant for the project's pre-feasibility study.

Son, also CEO of TEDI, one of the three firms, said the consortium has worked out that a top speed of 200 kilometers per hour proposed by the MPI would only cut track costs by 10 percent and equipment costs by 26 percent. 

"We have made detailed calculations for different speeds. There cannot be such a big difference in costs," Son told VnExpress. 

He pointed out that a speed of 350 kilometers per hour is needed to compete with aviation and other forms of transport. "By 2050 the high-speed railroad needs to carry a larger number of passengers than the nation’s roadways and airlines."

Over distances of 300-800 kilometers, a train traveling at 200 kilometers per hour would not be able to compete with other transport options, Son argued.

"China’s high-speed trains cover 30,000 kilometers, and Japan will soon have a 500-kilometers per hour train. We are already late by decades compared to other countries. A 200-kilometers per hour train shows a lack of vision."

But experts remain highly concerned about the cost. La Ngoc Khue, a former deputy transport minister, told VnExpress a cost of $58.7 billion would be "a burden on the economy."

It would mean the country’s budget for transport infrastructure must almost double for the next 30 years, and other projects would have to be delayed to prioritize the 350-kilometers per hour railroad, he said. "Doing something like this would be challenging, and construction might take 40 years or even more."

Superfast trains would not be able to carry cargo, and so trains running at 160-200 kilometers per hour would be optimal since they could also carry goods, he added.

The MoT said on Tuesday it would clarify the differences between its price tag and that of the MPI to the government before presenting it to the National Assembly for approval.

It revived the north-south high-speed railroad last year after it was rejected by the National Assembly in 2010 due to its $56-billion price tag, which was half of Vietnam’s GDP then.