The "morally bankrupt" former head of China's statistics bureau, responsible for calculating the country's economic figures, has been expelled from the ruling Communist Party for actions including "superstitious activities" and "insatiably" trading power for sex, a watchdog said Friday.

Wang Baoan headed the National Bureau of Statistics until January, when an inquiry into him was announced just hours after he spoke at a press conference in Beijing on China's economy.

In a statement on its website, the ruling party's Central Commission for Discipline Inspection (CCDI), its internal anti-corruption watchdog, said it had found Wang "completely lacks political beliefs".

He had "chronically engaged in superstitious activities, seriously violated political discipline and political rules, and in major issues has expressed views contrary to the CPC Central Committee", it said.

Questions have repeatedly been raised about the accuracy of official Chinese economic statistics, which critics say can be subject to political manipulation.

Wang is among the latest officials to fall to the much-publicised anti-corruption drive under General Secretary Xi Jinping, although critics say it can be used for internal faction-fighting, with its highest-profile victim the once hugely powerful security chief Zhou Yongkang, who was sentenced to life in prison.

The anti-graft campaign has been accompanied by an expansion of the rules governing apparatchiks' behaviour, including strict admonitions against publicly breaking party discipline.

The CCDI statement said Wang was "morally bankrupt" and that his offences included frequenting luxury hotels, indulging in expensive entertainment, and exploiting his position for sexual favours.

"Wang accepted gifts and money and used his influence to seek benefits and business conveniences for relatives and others, and is suspected of having committed bribery," it said.

The party decided to expel Wang due to his "serious violations" of party discipline, it said, adding that his case would be sent to judicial authorities.

Internal investigations into high-level party officials operate without judicial oversight. Once announced, they are likely to lead to a sacking followed by criminal prosecution, conviction, and a prison sentence.