Research showing some principals are skewing their schools' enrolment zones to avoid poor areas has sparked calls for a review of the entire school system.
A Fulbright scholar says some Auckland secondary schools admit deliberately skewing their enrolment zones in order to block enrolments by children from poor neighbourhoods.
School groups say the behaviour is driven by unhealthy competition and the Government needs to review the system of self-managing schools governed by boards of trustees, known as Tomorrow's Schools.
News of the skewed enrolment zones comes a week after Radio New Zealand revealed the number of Pakeha children at poor schools has halved.
School leaders and the American professor, Chris Lubienski, behind the school zone study blame the decile ranking system and excessive competition between schools, for both problems.
They say the system has resulted in too much competition.
Zones drawn to exclude poor areas
Professor Lubienski, of the University of Illinois, last year found 36 of the 49 secondary school zones in the Auckland area he studied do not match their immediate area.
In most of those 36 cases, Professor Lubienski said, the zones were drawn to include affluent neighbourhoods and exclude poor ones.
He said some principals told him they did it deliberately.
Professor Lubienski believes the schools want a high decile rating because people think that means they are successful.
He says some principals told him they tried to deter poor families in other ways. One said she removed the names of undesirable students from her school's ballot for out-of-zone enrolments.
He would not name the schools - they took part in the research on condition of anonymity.
Professor Lubienski said the term ''gerrymander'' is used in the United States.
The NZ Oxford Dictionary says gerrymander is named after Governor Gerry of Massachusetts who rearranged electoral boundaries in 1812.
Hard to believe - principal
However, the findings of dodgy zoning are questioned by one high school principal in Auckland.
Mount Albert Grammar School principal Dale Burden told Morning Report that he finds the accusations hard to believe.
He said zones cannot be easily manipulated and changing them is a transparent process.
Secondary Principals Association president Patrick Walsh says the ministry needs to review the research.
Statement by Ministry
The Education Ministry declined to appear on Morning Report on Monday, but has issued the following statement:
''The purpose of an enrolment zone is to ensure the selection of applicants for enrolment is fair and transparent and makes the best use of the school network.
''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 over-crowding.
''The ministry has recently updated guidelines on enrolments 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.
''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.
''If a school board is unable to agree a boundary arrangement the ministry can step in to resolve the matter. If necessary, the ministry has powers to require a board to amend a proposed enrolment zone.''