Mereana spent 14 years as a secondary school teacher of Māori Language and Physical Education. She moved into teacher education at Wellington College of Education, then took up a position at Te Wānanga o Raukawa where she spent 11 years training teachers for kaupapa Māori schools. In 2007 she became the first woman to fill the position of CEO at a Wānanga when she was appointed  Tumuaki of Te Wānanga o Raukawa. She is now the longest serving Wānanga CEO. Mereana is on a number or Boards, one of which she Co-Chaired; Te Mātāwai.  Te Mātāwai was established under Te Ture mō te Reo Māori 2016 (The Māori Language Act 2016). It’s role, as an independent statutory entity, is to lead the revitalisation of te reo Māori on behalf of iwi and Māori.

Although a 2nd language speaker of Māori herself, her five children are all 1st language speakers of Māori and were educated in Māori (Kohanga Reo, Kura Kaupapa Māori, Wharekura). Mereana has been active in the Māori language revival movement over the last 40 years, particularly with her own iwi of Ngāti Raukawa. She is especially interested in  language revitalisation and intergenerational language transmission. Before taking up the Tumuaki role Mereana spent some time looking at the contribution that technology can make towards the language learning process and to the survival of te reo Māori. The Te Ako Hikohiko experiment involved the bringing together of technology, education theory and mātauranga Māori in seeking some solutions to salvaging our endangered language. The many challenges that were faced during this experiment and the lessons learned have influenced the future direction that language and other learning is taking at Te Wananga o Raukawa.