There are two recent literature reviews on Māori language policy, undertaken for the Māori Language Commission by University of Auckland academics Tony Trinick, Stephen May and Ruth Lemon. Both are available here.
Trinick, T., May, S., & Lemon, R. (2020). Literature Review; Language Planning and Policy: Factors that impact on successful language planning and policy. University of Auckland/Te Taura Whiri i te reo Māori.
Trinick, T., May, S., & Lemon, R. (2020). Annotated Bibliography: Language Planning and Policy. University of Auckland/Te Taura Whiri i te reo Māori.
Other authors on Māori language policy include Nathan Albury, Richard Benton, Julia de Bres, Rawinia Higgins, and the late Bernard Spolsky.
Regrettably, most of the literature below is only accessible via libraries or requires some form of payment.
Benton, R. A. (2015). Perfecting the partnership: revitalising the Māori language in New Zealand education and society 1987–2014. Language, Culture and Curriculum, 28(2), 99-112. https://doi.org/10.1080/07908318.2015.1025001
A good overview of Māori-medium education is
May, S., & Hill, R. (2008). Māori-medium education: current issues and challenges. In N. H. Hornberger (Ed.), Can schools save indigenous languages? (pp. 66-98). New York: Palgrave.
(5) May, S. (2013). Indigenous immersion education: International developments. Journal of Immersion and Content-Based Education, (1)1, 34-69.
(6) Good introductions to language policy include;
Spolsky, B. (2004). Language policy. Cambridge: Cambridge University Press.
Spolsky, B. (2018). A modified and enriched theory of language policy (and management). Language Policy. https://doi.org/10.1007/s10993-018-9489-z
Spolsky, B. (2023). Rethinking language policy. Edinburgh: Edinburgh University Press. https://doi.org/10.1515/9781474485487
The Te Maihi Karauna is the Crown’s Strategy for Māori Language Revitalisation 2018 – 2023.
A rather grandiose scheme with little details on how it could be achieved.