She takes over at a time of concern as the committee is thought to be too weak, unable to instigate investigations of its own, hear appeals or interview witnesses.

Describing the present system as ''not unacceptable'', Ms Wong said she was most concerned at the way her committee monitored files to ensure impartiality.

She said she was aware of concerns among Legislative Council Security Panel members and pledged she would look at the committee's overall powers, including the ability to interview complainants.

Public perception of the PCC and the number of cases withdrawn, not sustained or pursuable, would also be examined.

''It's too early for me to draw any conclusions,'' she said. ''Having police to investigate police is not unique to Hongkong and if there are to be any changes it's important we look closely at different facts.'' Police morale, resources and administrative factors would have to be juggled.

The PCC has a staff of 20 while CAPO employs more than 200 full-time investigators.

According to figures published in the South China Morning Post on Monday, less than one in 50 complaints lodged against the police - and investigated by CAPO - were upheld.

Last year's proven rate of 1.9 per cent was the lowest since the PCC's inception in 1986 as a CAPO watchdog.

She said, however, that the figure covered all cases and did not account for the high number of files withdrawn, unsubstantiated or classed as unpursuable - reasons for which would all be studied.

PCC committee member Mr Justein Wong Chun said he hoped Ms Wong would work as a matter of urgency to make the whole complaint process more transparent and seek the ability to conduct independent interviews.

Ms Wong will meet CAPO officials next week to start her tenure.