An Education Review Office report shows the principal and some teachers at Pacific Christian School are not fully registered teachers.
The Education Ministry is suspending the school's registration at the end of this month because of fears for student safety.
It says the school's 70 students must find other schools to attend when the fourth term begins in October.
Pacific Christian School came to public attention in June last year when an 11-year-old boy stabbed another child in the head with a pair of scissors, badly injuring him.
Allegations of bullying following that event sparked investigations by police and Child Youth and Family. In May this year the Education Ministry asked the Education Review Office to conduct a special review.
The review report said the school's principal was not a registered teacher and two teachers had been stuck on provisional, rather than full, registration for four years because they had not been able to prove they had adequate advice and guidance.
The report said the school teaches children of primary and intermediate school age - years 1-8 - but some of its teachers were not trained to teach that age group.
"Some of the current teachers have come into the school with secondary teacher training and expertise. This does not always fit them well for teaching learners in their primary years. Few have recent training or qualifications."
The report also criticised what was taught.
Curriculum "not relevant"
"Teachers provide a curriculum that has little relevance to students' lives in New Zealand and does not support their language, culture and identity."
The report highlights health and safety shortcomings as well as problems with its approach to discipline.
"Procedural guidelines in the school are ambiguous in matters relating to discipline and behaviour management. Prohibition of the use of force by way of correction or punishment towards any student at the school is not well understood or clearly articulated by the Trust Board."
The review report said there was no assurance the school was doing enough to keep students safe and it recommended that the ministry review the school's registration.
"ERO considers that the Trust Board and school leaders do not have a clear understanding of their obligations as managers of a registered private school. In ERO's view, the welfare of students continues to be at risk."
Health and safety
Previous reports show the Education Review Office asked the school to improve its health and safety in 2009, but the school made little to no progress in addressing those problems.
The Education Ministry said it talked with the school's board on several occasions, but they were unable to be persuaded that children were not at risk.
It said the school's registration would be suspended from 25 September - the last day of the current school term.
"The suspension will remain in place until the school can satisfy us that students would not be at risk in terms of both their learning and safety and welfare. If that doesn't happen, we have the option of cancelling the registration."
The Education Council, which replaces the Teachers Council, is the body that registers and disciplines teachers. Its interim chief executive, Julian Moore, said the Education Ministry had alerted the council to the issue yesterday, and it had received information from the police.
"We are gathering evidence on what has happened, and will then decide whether disciplinary action should be taken. It is not possible to say how long this will take, but we are treating the matter as a priority."