Almost 130 reports have been received by the ICAC this year and most were related to the municipal council polls in March.

Despite a fall in most complaint categories, including a slight drop in allegations against police, the number of ICAC prosecutions jumped almost 25 per cent.

Some cases have been with the Legal Department for nearly four months.

ICAC head of operations, Jim Buckle, said the figures were an 'oddity'.

He said if the downward trend continued there would either be cause to celebrate or a need to learn why people were not reporting when intelligence suggested rising corruption.

'It does look a little low and they are interesting, but I think it is too early to start making predictions.

'I think we really have to wait until June to see how things are going,' he said.

'One of the interesting things is the increase in our prosecutions - our through-put has been better because for much of last year we were distracted by a few things happening.' Mr Buckle told a Legislative Council Security Panel hearing last week that he believed the pressures of responding to the inquiry into the dismissal of sacked ICAC deputy director of operations, Alex Tsui Ka-kit - and the review of powers and procedures - had affected efficiency.

Under the Corrupt and Illegal Practices Ordinance, the ICAC is compelled to look into all complaints, regardless of whether they infer corrupt conduct.

After September's elections only 86 of the 279 complaints were considered likely to involve graft.