An ex-aide of former Chinese president Hu Jintao has been charged with accepting bribes and illegally obtaining state secrets, prosecutors said on Friday, suggesting he will face jail after a trial.

The ruling Communist Party last year accused Ling Jihua -- once Hu's chief of staff -- of bribery and "trading power for sex", after expelling him the previous year.

Ling's son died in a notorious Ferrari crash in Beijing which disrupted a once-in-a-decade party leadership change in 2012.

The accusations against Ling are "extremely serious", the country's senior prosecutor said on its website, suggesting a lengthy sentence is likely.

He "abused his power" as director of the General Office of the Communist Party's Central Committee, where he worked under Hu, it cited prosecutors in the northern port city of Tianjin as saying.

While in several party leadership posts he "illegally received large amounts of property and obtained state secrets," it added.

His prosecution is likely to be followed by a tightly choreographed trial, with a guilty verdict and jail term almost guaranteed.

It comes as part of a high-profile crackdown on graft by current President Xi Jinping that has deposed several senior officials, notably former security chief Zhou Yongkang, who was jailed for life last year.

Critics say that a lack of transparency around the crackdown means it has been an opportunity for Xi to eliminate political enemies.

The 2012 car crash involving Ling's son scandalised China despite a mainland media blackout -- partly because two young women, one nude and one partially clothed, were also injured in the crash, with one reportedly dying months later.

Internet users questioned how the son of a party official could afford a car worth a reported five million yuan (around $800,000).

- Graft-buster -

The Communist Party said in July that an internal probe found Ling "violated political discipline and rules".

Graft is endemic in China's authoritarian system, and Xi has acknowledged it as a threat to the ruling party's survival.

Ling, 59, is among the highest ranking officials charged in recent years, after Zhou and former Politburo member Bo Xilai who was jailed for life in 2013.

Ling was "clearly" affiliated with the Communist Party's Youth League, an alternative power-base which has been under attack by Xi and allies in recent months, Steve Tsang, the head of Contemporary Chinese Studies at the University of Nottingham, said.

A delay of more than a year between the party's probe and prosecution reflects caution on Xi's part, he said, adding the president "can't fight all sides at the same time".

The announcement comes after months of negative indicators have increased doubt about the party's economic management.

"This is a good opportunity for Xi Jinping to re-establish his authority as the incorruptible graft-buster," China expert Willy Lam of the Chinese University of Hong Kong told AFP.

"This will promote his stature within the party".

The charges against Ling suggest he will receive "a very severe sentence - a suspended death sentence, perhaps," Lam added.

Such sentences are usually commuted to life in prison.

Ling's brother, Ling Wancheng has fled to the United States, a Chinese anti-graft official confirmed in January, adding Beijing was "in touch" with Washington about his case.

"It will be interesting to see whether his younger brother Ling Wancheng, under US government protection, would do anything to affect the case," Lam added.

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