The Office of the Ombudsman will investigate how the Official Information Act is used, the NZ Herald reports.
The public watchdog's probe comes in the wake of the Dirty Politics book, which sparked questions into the way in which OIA information was provided to WhaleOil blogger Cameron Slater.
Chief Ombudsman Dame Beverley Wakem said the issues examined will include government departments having to seek "sign off" from their ministers before releasing information when there was no reason to do so, the report says.
Dame Beverley is reported as saying there was "excessive reference upwards for approval" to release information .
The 30-year-old Official Information Act was intended to increase government accountability.