Teachers' and principals' groups say the Government will be risking children's education if it lets charter schools have fewer registered teachers than state schools.
The Government has announced details of how the publicly funded private schools will work, along with their name - Partnership Schools, or Kura Hourua - when they open as expected in 2014.
The Government says it is shifting from focusing on the inputs to education, like teachers and classrooms, to the outputs - students' achievement.
But the teacher unions and principals' groups say the plan will put children's education at risk because registered teachers are needed to deliver a good education and charter schools will be able to negotiate with the government how many registered teachers they have.
Under the plans announced on Thursday by Education Minister Hekia Parata and Associate Education Minister John Banks, although the people in charge of teaching must have experience in education, charter schools' chief executives need have no teaching experience.
'Disservice' to children
The president of the Principals Federation, Paul Drummond, says that is disturbing.
"It really undermines our very successful public education system," he says, "and it's saying to parents that it's okay to have unregistered and unqualified employees in schools - and I think that's a disservice both to the system and to our children."
Mr Drummond says the name Partnership Schools is an insult to state schools, which already work in partnership with their communities.
Labour's education spokesperson, Nanaia Mahuta, says there are risks associated with having unregistered teachers in classrooms.
"We want to assure ourselves that those people teaching our children have the qualifications and are appropriate to teach," she says, "and that standard should apply across the board."
Prime Minister John Key says, however, that the performance of the schools will be measured according to very strict criteria. He says a certain proportion of teachers will have to be registered.
National Standards must be followed
The schools will be run by sponsors under contract to the Government.
Radio New Zealand's education correspondent says the contracts will set targets for children's achievement and the schools must accept all applicants - running entry ballots if they are oversubscribed.
Primary schools will be required to follow National Standards and secondary schools to offer NCEA or another recognised qualification.
The sponsor will negotiate with the Government the number of registered teachers to be employed, their pay and conditions, what curriculum to use, the school's hours of operation and whether local people can help govern it.
Mr Banks says the model is unique to New Zealand and the schools will help address underachievement by some groups of students.
