BEIJING, Aug. 14 -- The China National Petroleum Corporation (CNPC) is to start an internal inspection on embezzlement of earnings after it was exposed for corruption in an earlier audit.

The move will focus on uncovering and clearing "private coffers" set up in all its subsidiaries, including PetroChina, according to a statement from the CNPC's internal disciplinary unit on Thursday.

Lower branches of the organization were found to hold a part of the company's profits to build their own private coffers, providing bonuses to employees or paying for extravagant consumption.

According to a National Audit Office report released in June, the corporation was found to have held back profits totaling 603 million yuan (98 million U.S. dollars) with some subsidiaries giving the embezzled money to staff.

Several affiliates of the CNPC have also been found avoiding open bidding for projects and purchases totaling 26 billion yuan.

The parent company asked all its subsidiaries to conduct a thorough self-check and form detailed reports, which will be read and signed by the corporation's highest leaders.

The inspection will also supervise the correction of irregularities uncovered by auditors, according to the statement.