The Education Review Office says some low decile secondary schools are nearly overwhelmed by their students' social needs.
In a report published on Wednesday, the ERO calls for more coordinated support for such students and better links between schools, families and communities.
The ERO said only 10 of the 74 schools it reviewed in the second half of 2012 are good at tailoring education to the needs of each of their students.
It says lower decile schools are generally less responsive to individual students than higher decile schools, and there is a significant link between deciles and the challenges schools face.
The report says some secondary schools use vocational courses to improve NCEA pass rates for Maori and Pasifica students, but very few try to do the same with academic courses that lead to university.
Secondary Principals' Association president Tom Parsons supports the call for more help for students in low decile schools.
"There are a lot of agencies out there working really, really hard. Sometimes it's not as coordinated as principals would like. If the end result is a student leaving school and going into a meaningful workplace, then yes we need to make it as easy as we possibly can. A more coordinated approach would be great."
Mr Parsons says schools have always needed help with students' health and social problems, and probably always will.