Prime Minister John Key is defending a deal with ACT which will set up charter schools in poor areas.
It's part of the support agreement signed with the party on Monday and teacher unions are strongly opposed to the trial.
Community
groups and non-profit private enterprise organisations will run some
state schools, outside the rules that cover the sector.
Boards of
trustees will set their own teaching practices, decide the length of the
school day and year, and pay teachers on performance.
Mr Key says some state schools are failing, particularly in poor communities.
"It's
a step towards more choice, at the end of the day I expect the vast
bulk of schools will be the same as they are now," he told Radio New
Zealand.
"There's thousands of schools in New Zealand - if we
might trial one or two to see whether they can deliver better results
it's a bit far fetched to say this is somehow undermining the education
system."
The Labour Party says National is trying to hoodwink
voters by bringing in education changes under the guise of a support
agreement.
Education spokeswoman Sue Moroney says National was working on charter schools before the election but didn't tell anyone.
Mr Key says ACT wanted the trial.
"I don't think voters are going to be up in arms because in a couple of communities we give a new model a go," he said.
"If students don't want to go to them they'll be free to go to state schools."
Mr Key says the trial could start next year but a lot of work has to be done first.
NZN