A Christchurch principal says competition between schools is damaging and the education system needs a rethink.
Shirley Boys' High School Principal John Laurenson told Nine to Noon schools in wealthy areas were attracting the most able students from poor areas and that accelerated social divisions.
Schools were not just poaching top sporting students, but those with cultural and academic ability too.
He said inter-school rivalry for the "right" students was rife.
Mr Laurenson has been a principal for 21 years and decided it was "time to speak up".
He wanted a think tank to come up with a new way of organising schools.
"We've got ghettoisation occurring in New Zealand - we've got the poor suburbs with the schools within it.
"I see the so-called elite schools getting stronger and stronger, and I see the poor schools getting poorer and poorer."
The sociological implications of that was "not good".
He said David Lange's "Tomorrow's schools" education reform in the late 1980s relaxed regulations, allowed schools to become "self-determining" and increased inter-school competition.
Because funding depended on student numbers, schools competed for pupils.
Schools in "leafy suburbs" snapped up children from poorer areas through scholarships and other means.
A school considered to be doing well was more likely to attract more students in future.
The "right" student was one that was an "asset" - be that in cultural competition, academia or sport, he said.
For schools, it made education less important than getting the "right" student.
"The brightest and the best will go where the parents perceive a superior education is to be found. That accelerates the problem... the social divide."
The elite schools polished the value that already existed. Poorer schools were adding value, but were not recognised for it.
Mr Laurenson acknowledged his school was as competitive as the rest.
He called on politicians to bring about national change and to redefine success - which was not winning Maadi Cup rowing competitions or having a top first rugby team.
He said elite schools should have to ensure students in low-decile areas, where failure was more common, succeeded as much as their own students.
"We should be lauding and praising schools for addressing the needs of young people so they can meet the demands of life in the 21st century."