Principals and the Green Party are calling for a review of the Tomorrow's Schools model which they say has caused secondary schools to adjust school zones and cherry pick students.
Concern has mounted after a report by a visiting US scholar found most Auckland secondary schools are zone-fixing - intentionally skewing their enrolment zones to improve their decile rating.
Principals say zone-fixing is nothing new and competition between schools has grown since the Tomorrow's Schools model was introduced under David Lange in 1989.
Fulbright scholar and Associate Professor from the University of Illinois Chris Lubienski looked at 49 secondary schools, comparing surrounding areas with the areas actually included within the zones the schools have drawn.
Professor Lubienski said that in 36 cases, the enrolment zones did not match the surrounding population.
He said he could only infer there was an intention by schools to distort their decile rating, although he said in the qualitative part of the study, principals talked about intentionally drawing up zones to enhance their school's market position.
He said one principal even said she removed the names of undesirable students from the ballot for out-of-zone enrolments.
"We found in a vast majority of cases that the schools were serving students who were more affluent,'' he said.
The schools took part in the research on condition of anonymity.
Green Party education spokesperson Catherine Delahunty said for a long time the party had been calling for a review of Tomorrow's Schools, but she said she would be nervous of an Act Party-led review.
"We feel there are some major issues with Tomorrow's Schools. We want to see a review that actually talks to the education sector.''
Head of the Secondary Principals' Council Allan Vester said the issue of schools selectively setting their school zones was not new.
"It has been discussed and debated for years. I very much doubt that the research findings come as a surprise to anyone who has been in Auckland since Tomorrow's Schools.''
He said aspects of Tomorrow's Schools should be reviewed.
"Unfortunately the market type model also encourages behaviours which, while advantageous for an individual school, can actually reduce the quality of the educational experience overall for the community.''
He said the decile system introduced in the 1990s did not alleviate the competition and inequality.
"At the core of the issue is competition. There was a belief that many schools were coasting along and a good dose of commercial reality would sort them out. If you didn't do a good job then parents would take their children elsewhere,'' said Mr Vester.
The Minister of Education has declined to comment on the allegations that school zones were manipulated by schools to avoid low-income families.
In a statement, the Ministry of Education said the enrolment zone was set up to ensure the selection of applicants for enrolment is fair and transparent and makes the best use of the school network.
It said householder income should not be considered when zones are drawn up.
"The law requires a board to ensure all students can attend a reasonably convenient school while ensuring other schools do not experience enrolment problems.
"As far as possible, an enrolment scheme must not exclude local students so that no more students are excluded from a school than is necessary to avoid overcrowding.''
The ministry had recently updated guidelines on enrolment zones. They make clear that before drawing up an enrolment zone boards are required to consult parents and the wider community as well as other schools.