Headmaster says local low-decile counterparts will not be able to compete.
Free uniforms and stationery are on offer to those who enrol at a new charter school.
Millions of dollars will be spent on new charter or "partnership" schools despite hundreds of spare places at surrounding state options.
However, the Government says the schools, which open next year, will offer parents a new model of education, and population growth means impact on existing schools will be minimal.
That has not stopped disquiet from one principal who says it is unfair to expect lower decile schools to compete with charter schools offering free uniforms, stationery and no donations.
Four new partnership schools will open next year, all in Auckland and Whangarei, joining the first five that were established this year.
Documents released yesterday by the Ministry of Education include information on how it expects the new schools' neighbours to be affected.
Six intermediate schools are near the site of Middle School West Auckland, a Year 7-10 partnership school that will have a maximum roll of 240.
The schools have enough spare places to enrol an additional 588 students at Year 7-8, according to the ministry document.
Roy Lilley, principal of Bruce McLaren Intermediate, which had 416 spare places, said he was concerned about the new partnership school.
"They are offering free uniforms, no donations ... totally free. The impact on local schools could be huge."
Alwyn Poole of the Villa Education Trust, which will open Middle School West Auckland, said its location had been determined by the ministry.
Partnership schools cannot charge donations, and the school would provide free uniforms and stationery, Mr Poole said, but not as "sweeteners".
"What we want is that every child walks through the gate at 100 per cent equal."
Mr Poole said that, despite attacks from opponents of charter schools, they did not get more funding, and start-up costs were well below usual amounts for state schools. Creative budgeting and a lack of expensive infrastructure like playing fields enabled them to offer smaller classes and items such as uniforms, he said.
In South Auckland, there are 12 schools teaching similar year levels to Te Poutoku Manawa, a charter school to be run by the Manukau Urban Maori Authority, which is headed by broadcaster Willie Jackson.
Te Kura Kaupapa Maori A-Rohe O Mangere is only at 55 per cent capacity, with other schools including Viscount School and Robertson Road School having more than 100 spare places.
The ministry report noted that many local schools were losing students, but said in general the student population is expected to increase and a large special housing area is planned nearby.
It does not expect enrolments at partnership schools to affect the operation of existing schools.