The new site, at 30 Humber St, is part of a $70 million Department of Corrections renewal programme to make corrections centre sites around the country more secure and better equipped to support offenders.
The site manages 84 offenders on 122 community-based sentences and orders that include home detention and community work, which covers the area from Palmerston to Waimate.
Four probation officers and a service manager are employed in Oamaru.
The building has two interview rooms specifically designed so high-risk offenders can be interviewed in a secure environment, a family room with audio and visual link capabilities, two multi-purpose meeting or training rooms, a secure document storage room, secure server room and staff area.
Department of Corrections acting national commissioner Ben Clark said the facility would allow for a more community-based approach to reducing crime.
"The inclusion of a space for community group use supports Corrections’ collaborative approach to reducing re-offending. Through this work, Corrections staff and local partners help create a safer community for everyone.
"From this site, Corrections staff and community partners will deliver rehabilitation and work and living skills programmes, as well as managing the sentences and orders of offenders."
Community Corrections centres managed offenders in complying with their sentences and orders, reduced their likelihood of reoffending, helped them become more productive members of society and kept local communities safe, Mr Clark said.
Oamaru service manager Stuart Bayles said the site would benefit offenders and their families, and make what was at times a trying process easier for them.
At an official opening ceremony on Friday morning, Department of Corrections Maori services adviser Philip Ngeru delivered a karakia and led a waiata before Mr Clark unveiled a plaque.
About 30 people attended the opening, including representatives from police, Safer Waitaki, the Oamaru legal fraternity and Waitaki MP Jacqui Dean.