Mental health advocates want more help available in schools, to stop major problems developing over time.

Currently only 515 schools have onsite help available, most of them low decile and deemed to have the highest need.

Ministry of Health's Director of Mental Health John Crawshaw says making school a safe space keeps students there, which has a major mental health benefit.

"The international evidence is quite clear, that failure to progress and complete your schooling, you have a 1.7-2 times greater likelihood of having significant mental health problems later in life."