"This bias has been more clearly documented in a study comparing students' achievement on standardised tests and teachers' overall judgements of achievement in National Standards.
"This bias is evident for Maori and Pasifika students, particularly for boys in writing. The concern is that students from Maori and Pasifika ethnicities are not only perceived by their teachers to achieve at lower standards than those from other ethnic groups given the same standardised achievement score, but also that this perception may be reflected in their expectations of these students and the opportunities to learn that are provided."
At primary and intermediate schools, 68.8 per cent of Maori students met or bettered the standard in reading in 2015, the most recent results available. That proportion was 65.4 per cent in maths, and 61.6 per cent in writing. Those results are relatively static since 2013.
National standards results for Pakeha children were 84.3 per cent in reading, 80.7 per cent in maths and 77.3 per cent in writing.
Maori Party co-leader Marama Fox is a former teacher and has spoken out about how her own son suffered discrimination at school, saying she demanded a change in teacher after one called him a "predator".
The mother-of-nine said one of her sons had been labelled by a long-term reliever teacher when he was in Year 11. The teacher had wrongly assumed he had stolen from another student's bag.
Fox told the Herald there was an unconscious bias among some teachers and, while not perfect, National Standards provided data that helped reveal the problem.
The unfortunate truth was many Maori and Pacific children could feel like "aliens" while sitting in the classroom, she said.
To change that teachers not only needed to learn about a child and their background, but also needed to open up themselves so a two-sided relationship could develop.
Fox said cultural competency needed to be made part of the code of conduct for teachers.
Education Minister Hekia Parata, who has overseen large increases in Maori and Pasifika achievement at NCEA level, said it is well documented that students will likely meet the expectations held of them.
"The challenge is to hold high expectations of every child," she said. "Teachers are professionals and understand the need to view every child and young person individually."
Parata said it was important to note teacher judgements were moderated by other teachers, and tools like the Progress and Consistency Tool (PaCT) were available. There were a range of funded programmes, support and tools to help build teachers' cultural competence, the Minister said.
"We expect all accredited facilitators to be able to support teachers and leaders to build their capabilities and we expect that schools will demonstrate shifts in their capabilities to support diverse students."
Lynda Stuart, NZEI president, said the idea teachers could be affected by unconscious bias against Maori and Pasifika students would be very concerning to her, and every teacher she had worked with.
"Improving Maori and Pasifika achievement is a goal of NZEI, and teacher members have told us they want to learn how to work better with our Maori and Pacifica students in culturally appropriate ways.
"We've been asking the Government to invest in the professional development to allow this to happen. What we need is a professional learning environment that supports both teachers and students to challenge their own biases and work towards a more just society for all."
Auckland University lecturer in education psychology Kane Meissel, whose research Timplerly referred to, said there were findings that even when two students had the same standardised reading or writing score, their national standard result would be lower if from a priority learning group, such as male, Maori, Pasifika or students with special education needs.
"We don't know for certain why this happens, and the development of the Progress and Consistency Tool may held to reduce the effect, but it does suggest that our system is not serving all of its learners well."
In 2014, a University of Auckland masters candidate said she was shocked by the responses of some teachers she interviewed for her thesis, which found teacher expectations were highest for Asian students, followed by Pakeha and Pasifika.
Expectations for Maori were much lower, the research found, despite Maori students' actual achievement being equivalent to that of Pasifika students and that 20 per cent were achieving at above-average level.