China Railway Sixth Group Co Ltd. has done well in constructing the line, but it lacks experience in putting the line into commercial operation, Minister of Transport Nguyen Van The said at a National Assembly session Wednesday.

The contractor was appointed by China according to the terms of a loan agreement beween the two countries, he added.

The project can only operate after the Chinese contractor finishes the remaining construction and receives safety certificates for the whole system, he said.

In order to evaluate the project safety, the Ministry of Transport has hired a number of foreign consultants, led by a French company.

"They can only guarantee the project’s safety if the Chinese contractor provides all the data correctly," the minister said.

For these reasons, delays in the commercial operation of Hanoi’s first metro line will likely continue, The said without giving a specific date for the opening.

Hanoi’s first metro line is one of five metro projects in Vietnam, all of them delayed for years, sending their costs soaring.

For instance, the cost of the Cat Linh – Ha Dong line has been overrun by $393 million, from the original $553 million, the transport ministry said.

Minister The noted that the cost overruns for this line and four other metro projects have happened because of the inexperience of contractors and management consultants.

"The lack of experience with urban public transportation has resulted in contractors and consultants making incorrect cost estimates, which later required many changes to the original version."

Construction of Hanoi’s first metro line Cat Linh – Ha Dong started in October 2011 and was originally scheduled for completion in 2013. But several hurdles, including loan disbursement issues with China that were only resolved in December 2017, stalled it for years. It recently missed its April-end deadline.

When completed, Hanoi’s first metro line will run from Cat Linh Station in downtown Dong Da District to the Yen Nghia Station in the south-west Ha Dong District.