The Chief executive of the Department of Corrections says there are too many middle managers in the organisation.
The department plans to combine prisons, rehabilitation and probation services into one team to save $10 million a year. The change would cost 140 jobs.
Ray Smith, says the current structure was intended to improve efficiency but has instead created replication.
The lost positions would be primarily in national and regional office management and support functions and would equate to 2% of the corrections workforce.
Affected staff will be contacted from Thursday.