BEIJING (REUTERS) - China's state assets regulator has named a new chief, more than three months after the previous chairman was removed under suspicion of graft.

The State-owned Assets Supervision and Administration Commission (SASAC) said late on Tuesday that Zhang Yi had been appointed, replacing Jiang Jiemin.

Zhang was previously SASAC's deputy head, and prior to that had worked as secretary-general for the ruling Communist Party's anti-corruption watchdog.

SASAC is a ministerial-level body run by China's cabinet and is directly responsible for more than 100 state-owned companies, including Sinopec, Asia's top oil refiner, and China Mobile , which runs the world's biggest network of mobile phone users.

Zhang will be expected to take a major role in reforming China's sprawling state sector as the Communist Party seeks to allow private investment into important sectors of the economy, such as energy, transport and finance, over the next five years.

In September, the Party's anti-graft watchdog announced it was investigating Jiang for "serious discipline violations", the party's general term for corruption.

President Xi Jinping has declared war on corruption, vowing to go after powerful "tigers" as well as lowly "flies".

Jiang had been promoted to head the regulator only in March, after serving as chairman of energy giant China National Petroleum Company (CNPC).

The Jiang probe came after four of CNPC's top executives were placed under investigation for alleged wrongdoing in late August.

Earlier this month, authorities put Zhou Yongkang, one of China's most powerful politicians of the last decade and CNPC's general manager from 1996-1998, under house arrest while they probe graft allegations against him, sources told Reuters.