Cases of "irregularities" at Industrial & Commercial Bank of China Ltd., Bank of China Ltd. and the country's other three State-owned banks fell 58 percent in the first half from a year earlier, the industry regulator said.

The amount of money involved in such cases declined 69 percent to 385 million yuan (US$50.7 million) during the period, said a statement posted on the China Banking Regulatory Commission's Web site last week. It did not define what constitutes an irregularity.

China is seeking to strengthen oversight of a banking industry burdened with US$171 billion of bad loans.

The country's biggest State-owned banks are trying to improve risk management systems and root out fraud following recent scandals.

Industrial and Commercial Bank of China and Bank of China were among eight banks cited last month for failing in their scrutiny of 4.5 billion yuan of loans that were allegedly illegally invested in stocks. The loans were made to China Nuclear Engineering Group and China Shipping (Group) Co.

China must set up a standardized system to punish and fine perpetrators, making the costs of committing wrongdoings higher than the potential gains, the statement cited Liu Mingkang, the banking watchdog’s chairman, as saying.