Christchurch Men's Prison had been involved in making and repairing bins over the past decade, and the Otago prison began the same work two years ago.
More than 80 offenders at the Milburn prison were provided with an engineering training opportunity each year.
Prison manager Jack Harrison said prisoners were involved in a wide range of activities, some for the prison community such as grounds, kitchens or library work, or in jobs for outside organisations such as the skip project.
''All these opportunities are intended to increase the offenders' employable skills and build good work habits, so they can obtain sustainable employment and break the cycle of offending,'' he said.
That demand for waste bins was driven from the Christchurch earthquake rebuild.
OCF had staff qualified in engineering, adult education and literacy and numeracy to deliver practical programmes.
Those prisoners involved in the technical trade training area could work towards level 1, 2 and 3 national certificates in engineering, national certificate in welding and forklift licence.
Last year, 95 prisoners achieved 3164 credits, 990 unit standards and 52 national certificates in welding, forklift driving, first aid and carpentry/building training.
Offenders were helped into jobs through a network of employers known to the Engineering and Release to Work staff.
OCF has also been building farm machinery in the Otago-Southland area.
Prisoners were not employees of the department and were not subject to the same wage rates, rights and remedies as workers in the private sector.
They could be paid an ''incentive allowance'' of 20c to 60c an hour.
Offender employment activity manager Rob McNicol said working on the skips helped keep prisoners ''engaged in meaningful activity, teach them new skills, help them to develop good work habits, develop pro-social skills and contribute in a meaningful way to the community.
''Offenders gain qualifications and lifelong skills that stimulate self-esteem and pride in paying attention to detail.
''Engineering skills cross over into other industry sectors such as construction, farming and manufacturing.''
