An East Coast secondary school says officials need to be careful when tinkering with a successful learning programme for Maori.
The Government says Te Kotahitanga is being expanded into a broader programme called Building on Success to help teachers lift achievement.
But Labour and the Green parties says the plan is being slashed to free up money for charter schools, which the Government wants to see introduced.
Wiremu Elliot, principal of Lytton High School in Gisborne, says Te Kotahitanga is peerless. He says its success in the classroom is visible and has seen nothing to match it in 20 years.
Mr Elliot says pupils benefit from Te Kotahitanga because they are asked about their learning and feel valued.
He says if changes are made to the programme, its chief designer Professor Russell Bishop needs to be involved.
The Education Ministry says Te Kotahitanga is not being cut or scrapped. Deputy secretary of schooling Rowena Phair says no school will lose services through the change.
The ministry says it is committed to raising achievement among Maori, as well as other groups.
Te Kotahitanga is operating in 50 schools throughout New Zealand.