Northland schools have recorded 1085 disciplinary incidents involving students so far this year, with almost 15 per cent of cases related to drugs.
The students have been stood down, suspended or permanently excluded, according to Education Ministry figures revealed to the Northern Advocate.
However, more children could remain in school if the Rubicon youth drug education and support programme was extended right across Northland, chief executive Jenny Rooney-Gibbs said.
The figures, released under the Official Information Act, show the number of students caught with drugs is declining.
Of the 158 drug-related incidents this year - 14.56 per cent of the Northland total - 12 led to a student's permanent dismissal from school. Mrs Rooney-Gibbs said the majority of the 158 drug cases were in the Mid and Far North as Rubicon worked closely with secondary and intermediate schools in Whangarei and Kaipara to deal with problems as they arose.
Rubicon aims to keep students in school while dealing with drug issues.
The programme worked alongside police youth aid section, schools, parents and other organisations to ensure students kept learning and got appropriate support.
"We think we are doing the right thing in the area we are working in, but we are not in the Mid or Far North.
"Rather than stand down, suspended or exclude a student caught taking or with drugs at school, we work with them.
"The minute you stand them down it's giving them no support and setting them up to fail," she said.
The student signs a contract to be drug free and agrees to regular drug tests at least once a month, and counselling, support and mentoring is put in place.
In just over 11 years Rubicon has dealt with more than 500 students, with an 85 per cent success rate of keeping students drug free and in school.
"Some of our people that have come through over the years are now in jobs like the police, armed forces and teachers, responsible careers that they would not have been able to do if they had got a drug conviction," she said.
"We help them understand the full implications of drug use, including on their health. Young people are still growing and drugs can seriously affect their physical and mental development."
Mrs Rooney-Gibbs said there was no one sector of society whose children took drugs at school, with cannabis the big problem, mainly because of its accessibility.
"Whangarei Boys' High School headmaster Al Kirk said drug use by Northland students was seasonal, peaking during the harvesting "on-season", March and April, with cannabis causing the most problems.
While Secondary Principals Association president Patrick Walsh said cannabis was the most common drug, more students were using synthetic cannabis products or "party pills", he said.