The request has been made of NJPT, a consortium led by Japan’s Nippon Koei, by the project’s investor, the HCMC Management Authority for Urban Railways (MAUR).

The review should cover all personnel, including those who have quit, the investor has said.

The request follows the discovery that steel used in beam support pads for the line did not meet contracted standards, a source told VnExpress Saturday.

Speaking on condition of anonymity, the source said personnel on the responsibility review would comprise those who have been working or have worked for NJPT from the time the project was still on the paper until the steps of approving materials, inspecting and assessing construction.

The agreement signed in 2012 between the MAUR and the line’s contractors, the Civil Engineering Construction Corporation No. 6 (Cienco 6) and Japan's Sumitomo Corporation, requires them to use a certain quality of elastomeric laminated bearings pads, which are reinforced steel plates sandwiched between layers of rubber.

The pads are designed for use in bridge and building construction as a beam support.

It has been found that the steel used for all the pads on the elevated section of the line and the depot has failed to meet that quality, the source said Friday.

This means that the consultant unit, NJPT, has failed to discharge its responsibility when inspecting materials used for the project.

The review result could lead to the investor withdrawing payments it has made to the consultant, the source said.

In October, one of the pads fell out from between two beams on the line on which cracks were seen.

In December, MAUR inspected all the pads on its own and found two were lighter than the required standard. It suggested that could have caused the cracks.

It said EB1 and EB4 pads on the elevated section weighed only 117 kilograms, or nine kilograms less than the agreed weight.

Earlier this month, a team of independent inspectors found another pad had moved from its position on the elevated section and does not fit properly. Around half the pads used were made in Malaysia and imported from South Korea. The rest were made in Japan.

To date, the contractor has not made any statement on the faults found.

The Ministry of Construction has also sent an inspection team to the site, but their conclusions have not been revealed yet.

The VND43.7 trillion ($1.89 billion) metro route No.1 is set to have 14 stations, three of them underground.

Work on the much-delayed project is more than 80 percent complete, according to latest reports.

The city is hoping to begin commercial operations of the metro line by the end of this year. In all, it plans eight metro lines running a total of 220 km.