The Education Review Office is worried that secondary school guidance counsellors are dealing with increasing workloads and more complex problems.
In a report issued on Tuesday the office said most schools have good guidance services, but about a third do not.
The report is based on visits to 49 secondary schools and wharekura, and interviews with 671 students earlier this year.
It said more students are seeking help for increasingly complex problems at all the schools and it recommends a review of funding for school guidance services.
Many of those problems are related to poverty, mental health, family dysfunction, bullying, relationships, and drugs and alcohol.
The report is part of a Government project aimed at improving young people's mental health.
