The 4,371 corruption reports led to the prosecution of 604 people in 272 cases, an increase of 20 per cent compared with the number of cases prosecuted in the previous year. The conviction rate was 83 per cent.

Responding to a new trend, the ICAC financial investigation section provided expert advice on complex probes involving more than 390 companies and over 1,400 bogus letter-of-credit transactions worth $6 billion in total.

'The lingering economic downturn continued to expose graft-related fraud cases in the financial and insurance sector,' an ICAC spokeswoman said. 'In better times the fraudsters can pay back the loans but in tough times they get revealed for the scams.'

She also welcomed the Complaints Committee report showing more than 38 complaints encompassing 109 allegations had been lodged against the ICAC. Seventeen complaints related to abuse of power by ICAC officers.

'It is a very good thing we have been under such stringent checks and balances,' she said. 'It offers a formal mechanism for people to file complaints. Whether or not it is true, it is being dealt with by an independent authority and in terms for our accountability that is a good thing,' she said.

'Despite occasional fluctuations in figures the proportion of complaints against ICAC officers received in recent years remained on a low level, especially compared to the upward trend of corruption reports and the persistently heavy caseload.'

Allegations of abuse of power by ICAC officers mainly concerned areas such as search, arrest/detention/bail and legal access. Misconduct allegations included such matters as officers being impolite and failing to explain the content of a search warrant