A case related to former Railway Minister Liu Zhijun, recently charged with corruption, was heard by Beijing No 2 Intermediate People's Court on Wednesday, but the media's request to hear the trial was denied, the Beijing Evening News reported.

The case's five suspects, including Hou Junxia?- the daughter of Ding Shumiao, investigated in a separate case related to Liu?- were charged with illegal business operations involving 3 billion yuan ($486 million), the newspaper reported.

Details were not available on Wednesday, as the media were banned from the courtroom, and lawyers in the case had signed confidentiality agreements requiring them to be silent about the trial.

But earlier media reports said that after Liu stepped down in the wake of an investigation in February 2011, the ministry staff were informed in August 2012 that Liu used his office to help Ding, chairwoman of Beijing Boyou Investment Management Corp, win bidding for high-speed railway projects worth 3 billion yuan in the past decade, which brought her huge illegal profits, according to the newspaper.

Hou's trial can be considered a prelude of the former railway minister's corruption cases, the report added.