Official documents show some schools are worried by Wanganui Collegiate School's bid to gain state funding.
The private school wants to become state integrated so it can get more government funding and reduce its fees.
Documents obtained under the Official Information Act show two schools opposed the bid, one supported it and three others said they did not oppose it.
All the schools expressed concern about competition for students among Wanganui secondary schools in a situation where student numbers were already decreasing.
There was also concern at the impact this competition would have on boarding schools in the lower North Island.
Some were worried that Wanganui Collegiate wanted to nearly double its roll to 600 students.
However, the government is negotiating integration based on a roll of up to 400.
