Teachers have been struck off the teaching register for almost 600 matters in the past five years for offences ranging from dishonesty to sexual contact with students.
Data supplied by the Teaching Council under the Official Information Act shows that teachers were barred temporarily or permanently for 128 matters of sexual behaviour or contact and 59 matters of "inappropriate behaviour (sexual non-contact, etc)" in the five years to the end of 2018.
The next most frequent reasons for deregistration were listed as "conduct" (62), alcohol and drugs (52) and dishonesty (51).
In total, teachers' registrations were cancelled or suspended for 583 matters, or more than 100 a year, although the actual number of teachers involved was less than that because some cases involved several matters.
The council's general manager of professional services, Pauline Barnes, said the numbers were "very small" as a proportion of the 102,800 teachers who were registered as at June last year.
"Even one case of teacher misconduct is disappointing," she said.
"However, the public and the profession have high expectation of teachers and the vast majority uphold those expectations.
"As with other professions, a small number fall below those standards and we have robust processes to respond in those cases."
High-profile cases such as former Whanganui teacher Paul Collins, who was sentenced to six months' home detention on sexual charges in 2017, create an impression that some teachers abuse their positions of trust.
By law, all teachers convicted of any offence punishable with at least three months in jail, such as drink-driving, must be referred to the council.
But other council data shows the cases listed as referred because of convictions averaged only 90 a year over the three and a half years to last June - about nine for every 10,000 teachers.
For comparison, 145 out of every 10,000 adults in New Zealand were convicted in the year to last June for serious offences, excluding minor traffic offences which are not punishable by at least three months in jail.
Cases referred to the council because of convictions appear to be trending downwards, dropping from 111 in 2015 to 87 in 2016, 76 in 2017 and 41 in the six months to last June.
Total disciplinary matters referred for any reason to what was then called the Education Council are also trending down from 399 in 2015 to 364 in 2016, 255 in 2017 and 116 in the first half of 2018.
The council's name was changed to the Teaching Council last September.
Matters leading to teachers' registrations being cancelled or suspended were much higher in the first two years of the data provided - 222 in 2014 and 130 in 2015, but only 76 in 2016, 73 in 2017 and 82 last year.
This appears to be due to a change in methodology so no clear trend can be seen.
Matters causing deregistration, 2014-2018*
128 Sexual behaviour/contact
59 Inappropriate behaviour (sexual non-contact, etc)
38 Relationship and employment matters
30 Aggressive behaviour and physical handling
11 Driving (counted under 'Other' until 2018)
*Note: Includes temporary suspensions as well as cancellations.