A bill that gives the Independent Commission Against Corruption and the Police Integrity Commission the power to launch prosecutions is set to be defeated in the upper house, with Labor and key crossbench parties voicing strong opposition.

The bill, introduced by NSW Attorney-General Gabrielle Upton, has been criticised by the Greens and the NSW Police Association who believe it removes vital checks on the agencies' power.

NSW Attorney-General Gabrielle Upton says a bill that gives the Independent Commission Against Corruption and the Police Integrity Commission the power to launch prosecutions clarifies the agencies' powers. Credit:Cole Bennetts

Ms Upton argues that the bill, part of which amends the Criminal Procedure Act to ensure police and "public officers" have authority to commence proceedings for common-law offences, simply clarifies the agencies' powers.

It was deemed necessary after two local court judgments questioned ICAC's powers to instigate criminal proceedings.