Programmes are taught in an uniquely Maori environment and based on a teaching method called Ako Whakatere, which provides an inclusive, interactive and nurturing experience.
Ms Mihaka said she believed te reo was a dying language a few years ago but not now.
"There are so many professionals now teaching te reo and we are keeping it alive," she said.
Te Wananga o Aotearoa provides a range of fee-free programmes that can also be studied from home through Open Wananga.
Ms Mihaka said Maori language should be made available to all mainstream schools.
"We are lucky here, te reo is definitely promoted in Rotorua but it is not really promoted nationwide. If there was more support, te reo could be taught in mainstream schools."
Waiariki Institute of Technology head of department Maori development Terry Kapua said various levels of people want to take te reo classes.
"We have a real range of people who are full-time studying towards our degree in Maori Development or members of the community who just want to improve their knowledge."
Full-time students take the course across a year and most part-timers do it for a couple of nights a week across two years.
During the institute's Summer School, generally November to February, Te Puawai, a 15-credit level five course, introduces students to te ao Maori (the Maori world), including te reo Maori, waiata and Maori society.
"We've been trying to expand our reo courses because there is a lot of different levels of ability out there.
"Te Puawai was originally developed for the internationals who come here wanting to learn about our culture but it appeals to all because it looks at the Treaty of Waitangi and Maori social structure," Mr Kapua said.
For more information call Te Wananga o Aotearoa 0800 355-553 or Waiariki Institute of Technology 0800 924-274.
For free resources, visit www.korero.maori.nz or www.tetaurawhiri.govt.nz.
MAORI LANGUAGE WEEK:
At the 2006 census: 131,613 (23.7 per cent) of Maori could hold a conversation about everyday things in te reo.
One-quarter of Maori aged 15 to 64 could hold a conversation in te reo.
Just under half (48.7 per cent) of Maori aged 65 years and over could hold a conversation in te reo.
More than one in six Maori (35,148 people) under 15 could hold a conversation in te reo.