"The world of education is like a closed shop. What goes on behind closed doors, despite having a board of trustees who are members of the public, isn't always spoken about and that is because the schools have to protect their reputation."
Teachers were able to get away with performing poorly because schools did not want to be seen sacking a teacher, she said.
"What tends to happen therefore is that teachers who basically shouldn't be teaching are often just put up with.
"It is really hard to get rid of a teacher."
During 2014, 12 teachers were reported for relationship and employment matters, 17 were reported for competence, four were reported for dishonesty/fraud, two were reported for sexual behaviour and contact while one was reported for viewing pornography. These reports did not result in convictions.
A further 16 teachers were criminally convicted - nine for drugs and alcohol, three for dishonesty/fraud, three for driving and one teacher for violence.
In 2013, 11 teachers were reported for relationship and employment matters, nine were reported for competence, two were reported for dishonesty/fraud and three were reported for violence.
A further 13 teachers were criminally convicted for drugs and alcohol, two were convicted for violence while one teacher was convicted for driving offences.
Post Primary Teachers Association national president Angela Roberts said schools now had a better understanding of what they were required to report but the competitive school market meant issues were sometimes hidden.
"The best decisions aren't always made when you have a competitive model where you are incentivised to hide things," she said.
"I'm not surprised that you have people who have that perception because I'm pretty sure occasionally it happens."
Schools needed to collaborate more to avoid competition and invest in the staff they had, she said.
New Zealand School Trustees Association president Lorraine Kerr said said the statistics were "shocking".
"You wouldn't want any of our teachers in New Zealand to have that [a criminal conviction] beside their name."
While 16 criminal convictions seemed high there were more than 180 schools in the Bay of Plenty with an average of six teachers at each so the proportion was low - "but not low enough", she said.
New Zealand Principals' Federation president Denise Torey said the threshold which required schools to make a report to the Teachers Council was very low. A lawyer then looked at the reports and decided which needed to be investigated further and which could be thrown out, she said.
"On the whole the Teachers Council are seeing more reporting and that's because principals are aware of it as well."
Despite that, 16 convictions was a concern, she said.
"We don't want those people in our schools that aren't great role models for out kids."
Ms Torey said it would only be a small percentage of schools that would try to hide or ignore issues.
"I think that's an exception rather than the rule."
Teachers Council acting director, Rob McIntosh, agreed reports increased after nationwide workshops in 2013 and 2014 to ensure teachers and principals were fully aware of their responsibilities.
"In 2014, a change was made to Council rules which requires all hearings of the Disciplinary Tribunal to be held in public, unless there is a compelling reason not to do so (e.g. vulnerable witnesses).
"The rule change also removed automatic name suppression for teachers in written Disciplinary Tribunal decisions. This change means teachers, students and parents can be fully aware of sanctions imposed against a teacher - this acts as a deterrent, and an accountability measure."
