Charter schools will create more problems than they propose to solve, unions and principals say.
They say the schools, by employing untrained teachers, contradict the Government's push to raise academic achievement.
Charter schools, which could open in Christchurch as early as 2014, can set their own staff pay rates, choose their own staff and set curriculum and term dates.
Education Minister Hekia Parata and Associate Education Minister John Banks have announced a framework for the New Zealand Model of Charter School.
Correspondence released under the Official Information Act shows the Canterbury Ballet Academy and a "small group of educators" have indicated an interest in opening charter schools in Christchurch.
Legislation will be introduced to Parliament this year and schools will open for the start of the 2014 school year.
However, they must abide by the national standards and must offer National Certificate of Educational Achievement or equivalent recognised qualifications.
Parata said the schools would focus on raising achievement for all pupils, particularly for those historically let down by the current system.
Lee Walker, principal of Linwood Intermediate School and chairman of the Christchurch Association of Intermediate and Middle Schooling, asked what problem charter schools would fix.
"Where is the rationale with what the problem is?" he said.
"Initially it was the education system that was failing. Then, after charter schools were announced for Christchurch, it was that the schools in the eastern suburbs were failing. Nobody has ever said what those schools are failing on."
He said schools already had some freedom to set term dates and opening hours.
New Zealand Educational Institute president Ian Leckie said employing untrained teachers was unlikely to raise pupil achievement.
“How can the Government say it wants to improve the quality of teaching while at the same time allowing unqualified teachers into the system?” he said.
Post Primary Teachers' Association general secretary Kevin Bunker said it was "crazy" that skilled tradesmen had to be registered, but not teachers at charter schools.
- The Press
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