Subsidence and flooding at the recently opened Nanjing South Railway Station on the high-speed Shanghai-Beijing route has raised more doubts about the rail project.

Torrential rain hit the capital city of east China's Jiangsu Province on Tuesday. According to a report on Jschina.com.cn, a local news portal, water leaked from the roof of the transit hall of the station and several buckets were being used to collect the water.

Marble tiles cracked after being submerged in the water and walking on them felt like stepping on cotton while muddy water splashed up from around the edges, the report said. In some places where the flooding was most serious, the water reached above ankle level.

Subsidence at the station also made the ground uneven, the website said.

However, a senior rail official said subsidence was to be expected in a newly constructed area where cables had been laid underneath. It wouldn't affect the structure of the station or the operation of the bullet train, said Bao Wenqi, deputy commander in chief of the station's construction headquarters under the Shanghai Railway Bureau.

The downpour renewed concerns over the station's quality, reinforcing criticism that the station had been completed too hastily.

Floor tiles in the station's north square, covering up to 4,000 square meters, had been dug up less than 10 days after the station was put into operation and new tiles were to be laid in the area, local media reported previously.

The contractor of the project, Nanjing Railway Engineering Investment Co said the original tiles were a temporary measure so that the station could open to the public before June 30, the day the high-speed route officially opened.

New tiles would be laid to ensure the quality of the project, an official said.