Qian, a partner at the East Associates Law firm and director of the Beijing Bar Association's criminal law committee, declined to elaborate on those or detail the amount of bribes Liu was alleged to have accepted.

Liu, who was fired in February 2011, oversaw a massive expansion of the mainland's high-speed rail network in the preceding decade. But that expansion also left massive debts and was tarnished by a high-speed train crash in Wenzhou in 2011 in which 40 people died. He was charged with corruption and abuse of power in April.

Liu will be the first minister-level official to be tried since the new government leadership was installed in March. President Xi Jinping , as Communist Party general secretary, has pledged an iron-fisted approach to tackling corruption within the ranks.

The trial brings to mind another high-profile case, the anticipated trial of Bo Xilai, the former Chongqing party secretary and member of the party's powerful Politburo, who has been under criminal investigation but is yet to be formally charged after more than 15 months in detention.

Media reports have described Liu's case as "very serious", involving bribes linked to rail construction projects worth up to 60 million yuan (HK$75 million). He reportedly accepted about 40 million yuan from Shanxi businesswoman Ding Shumiao alone in return for the 3 billion yuan in high-speed-rail contracts she is said to have won.

Ding also reportedly arranged for Liu to have sex with young women, including actresses from the television drama series , in which her firm invested.

Ding's daughter, Hou Junxia , and four other middlemen stood trial at the Beijing No2 Intermediate People's Court in April, charged with running illegal business operations in the high-speed-railway bidding process. No verdicts have been handed down.

Under mainland law, accepting bribes of more than 100,000 yuan can be punished by death.

The last senior official to be executed for corruption was State Food and Drug Administration head Zheng Xiaoyu , in 2007.