As the country steps up efforts to root out corruption, auditors are playing an important role in tracking down irregularities in State-owned enterprises, and 4 billion yuan ($640 million) of public money has been retrieved so far.

In a National Audit Office report released on Sunday, 13 of 14 SOEs audited were found to have violated rules of procurement and bidding. The money restored was only a fraction of the total haul of the nearly 160 billion yuan involved.

The office said more than 250 people had been disciplined and 56 cases involving "serious violations of Party discipline and laws", had been handed over to anti-graft departments and law enforcement entities.