Former top Chinese military leader Guo Boxiong has confessed to bribe-taking, the official Xinhua news agency reported Tuesday, citing military prosecutors who described the sums as "extremely huge".

Guo was for a decade one of the two vice chairmen of the Central Military Commission, second only to the Chinese president in the top body of the People's Liberation Army (PLA). He retired in 2012 and was expelled from the ruling Communist Party last year.

His fall came as President Xi Jinping seeks to consolidate his power and enhance his control over the PLA, the world's largest military and technically the armed force of the ruling party rather than the Chinese state.

Guo was found to have taken advantage of his position "to assist the promotion and relocation of other people, accepting an extremely huge amount of bribe personally and through his family", Xinhua cited military prosecutors as saying in a statement.

The 73-year-old had been formally charged and the procedure to prosecute him had begun, it added.

In China criminal charges normally follow expulsion from the ruling party. Trial, conviction and a jail term is effectively guaranteed to follow in a court system controlled by the Communist Party.

Since coming to power Xi has sought to impose his authority on the military, one of the targets of his wide-ranging anti-corruption drive.

As well as being the world's largest active military, a vast network of businesses are linked to the armed forces -- so extensive that academics have dubbed it "PLA Inc". Officials have said it will be fully barred from providing "paid services" in three years' time.

Graft is endemic in China and critics say that without systemic reforms Xi's campaign is open to being used for political infighting.

The hugely powerful former security chief Zhou Yongkang, who was sentenced to life in prison last year, is its most high-profile scalp, while another former Central Military Commission vice chairman, Xu Caihou, died of cancer while under investigation.

Along with Bo Xilai, whose fall predates Xi's ascension to the highest office, Guo is the fourth former member of the ruling party's 25-strong Politburo to fall.

- 'Anti-corruption sword' -

Guo "confessed to his suspected crime of bribery", Xinhua quoted an official of the military procuratorate as saying.

Prosecutors had taken a "highly responsible attitude to the law and to history", the official said, and seized money and properties involved "in accordance with the law". Others involved who had committed crimes would be punished "without tolerance".

Guo read and signed each interrogation transcript, the official said, adding his legal rights had been "earnestly guaranteed".

Military prosecutors could not be reached for comment.

Chinese media poured scorn on Guo after he was expelled from the ruling party last year.

"One demon killed, all demons deterred," declared a commentary in the People's Daily, the party's official mouthpiece.

"We must raise high and wield the sharp anti-corruption sword, so that the idea of going corrupt will be nipped in the bud and the corrupt will pay a price."

Guo's family built up an enormous fortune after he ascended to the highest echelons of power, news portal Netease.com reported at the time of his expulsion.

His wife He Xiulian acted as a broker between him and senior military officers, taking bribes for promotions and refunding the money if the post did not materialise, it said.