About $4.5 million will be saved over a decade from reduced prisoner transportation, including in Otago.
The Department of Corrections spent about $5.8 million transporting prisoners nationwide in the 12 months to June 30.
That figure did not include ''facility-related and corporate overheads'', Corrections Services deputy national commissioner Maria McDonald said.
She was responding to an Otago Daily Times request for data under the Official Information Act.
Corrections was unable to separate the cost of transporting Otago Corrections Facility prisoners from its national costs overall.
It was also unable to separate the cost of court-related prisoner transport, both at a prison level and national level.
Overall transportation costs included transfers to hospitals and ''a small number of other appointments''.
The department expected to save about $4.5 million from its total prisoner transport costs in the 10 years to 2020, with the full installation of an audiovisual link system in prisons and courts nationwide.
The AVL system meant some prisoners would not need to appear in courts and was due to be installed in the Dunedin court and Otago Corrections Facility in February 2015.
Corrections estimated the system would cut the number of court hearings requiring prisoner transportation by 50% to 70%.
In 10 years, that would equate to a saving of about $2.5 million in transport costs, and about $2 million in staff costs.
''These projections begin from the 2010-11 financial period and are dependent on the programme of work to install AVL facilities, and the level of uptake by judiciary, counsel and other parties to court hearings,'' Ms McDonald said.
The system's added benefit of reducing the risk of prisoners escaping in transit was a major factor in the decision to implement it, which was expected to cost about $28 million.
''A prisoner escape can pose a significant risk to the safety of staff and the public and lead to financial costs across the justice sector. Furthermore, the implementation of AVL will also allow for the more productive use of staff time.''
Fewer prisoners being transported meant Corrections would probably have space in its vans for prisoners at present being escorted by police, she said.
In the 2011-12 financial year, 1834 prisoners were transported between the Otago Corrections Facility and courts.
Police estimated they were involved in about 500 such trips a year. At least two police staff had to accompany prisoners being transported between jail and courts, and more were assigned if a prisoner was deemed high risk.
Once fully installed, AVL was expected to be used in most of the 40,000-odd remand court appearances in New Zealand each year.
