Chinese authorities have formally stripped the ex-director of Shanghai's free trade zone of his official posts and accused him of graft including "trading power for sex", according to a statement on Tuesday.

Ai Baojun, also a vice mayor of Shanghai, has been relieved of his government and Communist Party positions, the ruling party's corruption watchdog said.

The Central Commission for Discipline Inspection announced two months ago that Ai was under investigation for "severe disciplinary violations", which typically refers to corruption.

The commission on Tuesday detailed his alleged misdeeds, saying they included accepting gifts and money as well as abusing his position to benefit himself and others.

Ai previously held the title of director of the Shanghai FTZ, China's first free trade zone which was set up in 2013 with the stated aim of being a testing ground for economic and governance reforms.
He had been one of several Shanghai vice mayors since 2007, holding the portfolio for development and planning, and previously worked at Shanghai-based metals giant Baosteel.

The agency said Ai violated party discipline by visiting private clubs and playing golf, as well as "trading power for sex".

Some of his suspected crimes involved the management of an enterprise, the statement said, suggesting they may date back to his time at Baosteel. 

Investigators had passed the case to the judiciary for punishment "under the law", it said.

Since Xi Jinping took office as president three years ago, China has launched an unprecedented anti-corruption campaign, vowing to target both high-level "tigers" and low-ranking "flies", although critics say it is open to being used for internal faction-fighting.

Chinese media has said that Ai is the highest-level Shanghai official to formally come under investigation in the anti-graft drive, calling him the city's "first tiger".