Schools have consigned the Treaty of Waitangi to the bottom of a list of principles they must observe in their work.
The Treaty is number two in a list of eight principles that includes high expectations, community engagement and learning how to learn.
Despite this, the Education Review Office (ERO) says it is the least observed of the principles that have underpinned the curriculum since it was revised nearly three years ago.
In half of 109 schools visited by reviewers, ERO says the Treaty was either the least evident principle in their curriculum or not evident at all.
Instead, schools were focused on high expectations and community engagement.
Principals agree recognising the Treaty helps to create a positive, bicultural school.
But they say it can be difficult to realise if schools do not have teachers familiar with te reo and Maori culture.
ERO head Graham Stoop says he is disappointed by the finding.
"This is foundational to the country, it is foundational to the curriculum, and we do not believe schools should be having trouble with this. It's about forging links with your local Maori community and giving effect to those bi-cultural policies in the school, and in the classroom."
ERO has recommended the Ministry of Education supportS schools to implement the Treaty.