More than 20 teachers have had their registration cancelled after being convicted of sex offences in the past five years.
And more than 330 have had allegations of sexual misconduct made against them.
This year alone, five teachers have been struck off and 82 have faced or are facing allegations.
The Teaching Council provided the number of sex-offending teachers to the Herald under the Official Information Act after a Herald investigation into a teacher who sexually abused children over an almost 30-year period.
Paul Roger Herrick, 72, is behind bars for historical sex offending against pupils.
Herrick had been jailed three times previously for identical offending in between 1963 and 1993.
The Teaching Council revealed that from 2015 to July this year, 23 teachers have had their registration cancelled as a result of a conviction for sex offending.
It could not confirm how many of those offences were against children or young people in the teacher's class or care.
In 2016 eight teachers were struck off and already this year five have had registrations cancelled.
Allegations against teachers that "include reference to sexual misconduct" have reached 82 this year - on track to surpass the 92 in the whole of 2018.
A Teaching Council spokeswoman said allegations varied in seriousness - from an inappropriate joke through to a specified offence of a sexual nature.
While some teachers were struck off, others were censured or had conditions placed on their practising certificates.
Some complaints did not result in any action and some were still under investigation.
"Having just one case a year is a concern," said the spokeswoman.
"We want the best people teaching our children and we take action against anyone who does not meet the high expectations the public and the profession has of teachers."
Concerns and complaints came to the council from mandatory reports from schools or centres, complaints from parents or others, or reports that a teacher has a criminal conviction.
"If a teacher is convicted of one of the criminal offences listed in the Children's Act 2014 - a range of serious crimes mostly involving violence and sexual abuse - their registration is immediately cancelled," she said.
Those offences include a raft of sex crimes and indecencies against children including grooming, exploitation and inappropriate communication.
The National Party's education spokeswoman, Nikki Kaye, said the figures are concerning.
She called on Education Minister Chris Hipkins to have a "transparent discussion" about whether improvements to the current vetting system are needed to better protect young people.
"We need to continue to be vigilant as a community to improve our systems and procedures to keep children safe," she said.
"It seems like a pretty high number to me ... we need to have a situation where children are safe ... there are questions to be answered."
The Teaching Council said it is also important to note that, in context, a "very small" number of teachers were struck off for sex offending.
"There are more than 100,000 teachers in New Zealand … The vast majority are utterly trustworthy and competent," the council's spokeswoman said.
"It would be a disservice to the hard work and integrity of the majority of teachers to let the small number of those who are not promulgate a negative perception of the entire profession."
Recent examples of teachers convicted of sex offending include:
• In March 2016 Mark Robert Ashby was struck off after he was convicted of grooming and sexually assaulting a 14-year-old in Christchurch.
• Raymond George Melrose was struck off in November 2015 after he was convicted of indecencies and sexual assaults on young boys.
• In 2015 Dunedin teacher Toni Finch had her registration cancelled after she had a sexual relationship with a Year 13 student at King's High School.
All allegations of concern about teacher conduct were investigated by the council.
But Ministry of Education spokeswoman Katrina Casey weighed in on the matter.
"Nobody can or should consider that it's acceptable for anyone to offend against children under any circumstances," she said.
"There are many thousand teachers and by far the vast majority take the safety of children and young people extremely seriously and do everything in their power to keep them safe.
"Unfortunately, despite all the checks and balances and systems and guidelines a very small number of people have been caught offending against children and young people.
"One is one too many but despite the most robust processes, sometimes this occurs – what we know is that when it does happen, action has to be and is swift and children and young people subject to such offending must be well supported."
Casey explained that in 2012 the ministry, council, Oranga Tamariki and police signed a memorandum of understanding outlining the agencies' respective roles and responsibilities around allegations and offending.
The introduction of the Vulnerable Children Act 2014 made it mandatory for anyone working with kids via state-funded services - both teachers and "core children's workers" - to be vetted and screened before they were hired, then every three years after.
The act also required schools to have child protection policies in place, to encourage early identification and referral of suspected child abuse or neglect.
New Zealand Principal's Federation spokeswoman Liz Hawes said there was "no place in teaching" for a convicted sex offender.
"The NZPF has been very involved in the development of the complaints processes for the Teaching Council and indeed the standards for the teaching profession," she said.
SEXUAL HARM - DO YOU NEED HELP?
If it's an emergency and you feel that you or someone else is at risk, call 111.
If you've ever experienced sexual assault or abuse and need to talk to someone contact the Safe to Talk confidential crisis helpline on:
• Text 4334 and they will respond
• Email email@example.com
• Visit https://safetotalk.nz/contact-us/ for an online chat
Alternatively contact your local police station - click here for a list.
If you have been abused, remember it's not your fault.