China's ruling Communist Party formally expelled former railways minister Liu Zhijun on Sunday, paving the way for his trial over alleged bribe-taking involving 800 million yuan ($128 million), state media said.

The news came as hundreds of senior party members held a four-day closed-door meeting that ended on Sunday to finalise leadership decisions ahead of a ten-yearly power handover this month.

The Central Committee "endorsed a decision made by the Political Bureau... to expel former Railways Minister Liu Zhijun", Xinhua state news agency reported, referring to the party's top 25-member policy-making body.

The committee also expelled disgraced politician Bo Xilai over corruption charges, named two new military vice-chairmen and approved a draft amendment to the party constitution, without providing specifics.

Bo had been tipped for a top spot in the leadership transition this month but fell from grace earlier this year after his wife was found to have murdered a British associate, in China's biggest scandal in years.

Party authorities had announced in May that they planned to oust Liu and hand his case to the judiciary. Expulsion from the party typically comes before a court trial.

State media said previously that Liu, who was appointed in 2003 and sacked last year, faced investigation for allegedly taking payouts while handing out contracts for the rapid expansion of China's high-speed railway system.

The network, the largest in the world, has been plagued by graft and safety scandals.

The state auditor said last year that construction companies and individuals have siphoned off 187 million yuan in funds for the construction of the flagship high-speed railway line between Beijing and Shanghai.

A crash near the eastern city of Wenzhou in July last year that killed 40 people -- making it China's worst rail accident since 2008 -- sparked broad concern about the safety of the ambitious high-speed rail system.