The contribution volunteers have made to the Otago Corrections Facility (OCF) will be recognised and celebrated at the prison this afternoon.
As part of National Volunteers Awareness Week, the Department of Corrections is hosting a series of morning and afternoon teas to thank the 3000 people who volunteer in its prisons.
Some special awards are expected to be presented at the Milburn gathering.
National volunteer co-ordinator Russell Underwood said the number of people giving up their spare time to make a difference in the life of a prisoner was increasing.
"We've seen the number of volunteers entering our prisons increase by 6% since the beginning of the year, which is fantastic from our point of view."
Volunteers came in many shapes and forms, with many belonging to specific organisations while others were individuals, Mr Underwood said.
"Our volunteers represent a total of 443 voluntary groups, and 85% of those of those that volunteer in prisons belong to faith-based organisations."
The support volunteers gave prisoners was vital to their rehabilitation, he said.
Organisations like Prison Fellowship New Zealand and Toastmasters provided prisoners with communication skills and building their self confidence at the same time.
Others like Alcoholics Anonymous, which had worked with the department for 20 years, provided ongoing support and education to help prisoners fight their addiction.
