The Prime Minister has replied to criticism over charter schools, saying there are already teachers in the public school sector who are not fully qualified, mainly in technology classes.
The new Charter schools will be run by sponsors under contract to the Government.
The sponsor will be free to decide how many registered teachers to employ, what curriculum to use, and the pay and conditions of employees.
Secondary Principals Association president Patrick Walsh says the schools could damage New Zealand's reputation by employing unregistered teachers and chief executives without teaching skills.
However, John Key says not every teacher in state schools is fully qualified.
The association and other education groups say the Government should address under-achievement through the existing state school system.
Separately, New Zealand Principals' Federation president Paul Drummond says he wants a guarantee there will be a qualified teacher standing in front of each child.
The first charter schools will open in 2014 and will employ non-registered teachers and can be run by chief executives with no school experience, but the Government says the schools will help under-performing students.
Mr Drummond told Morning Report the solution to underachievement is a community response of which schools are a part, not setting up a new school system to compete with existing schools.
Ministry of Education figures from 2006 show 2% of primary school teachers and 6% of secondary teachers did not have teaching qualifications.
The primary school union says most people do not want charter schools to have fewer registered teachers than state schools.
The NZ Educational Institute says 86% of respondents to a survey conducted on its behalf agree the government-funded, privately-run schools should be allowed to hire only qualified teachers.
The UMR Research survey of 1000 people was conducted at the end of July.
NZEI president Ian Leckie says schools use unregistered teachers only as a last resort and for short periods of time.