China's top anti-graft watchdog said it is urgently tightening the Party's grip on the state-owned enterprises after a string of corruption cases were exposed.

Inspections at SOEs revealed leaders abusing their power for personal gain and benefitting relatives at the expense of public interest, the Communist Party of China (CPC) Central Commission for Discipline Inspection (CCDI) said in an article published on its website Monday.

"Some people embezzled state assets under the name of carrying out reforms at the SOEs while others tried to corrupt senior officials using illegally obtained state resources," it said.

Leadership at certain state firms also ignored the CPC's promotion protocol, deciding on their own who to promote, the graft watchdog said.

The CCDI launched an anti-graft inspection targeting 26 firms, mostly energy and communication giants, in March.

Six major state-owned enterprises, including the China National Nuclear Corporation and China Nuclear Engineering Corporation, were scolded publicly for bribery, nepotism and management loopholes which led to loss of state assets.

The fundamental reason for such violations is lack of a powerful CPC leadership in state enterprises, resulting in flagging faith in the Party and lax discipline among the members, the CCDI said.

"The key to building up competitive SOEs relies on strengthening the CPC leadership while deepening the reform," the CCDI said.