Head of sector enablement and support Katrina Casey said a staff member had met Datacom and she had followed up with a letter outlining their disappointment.
A Datacom spokeswoman told the Herald their truancy management team, which works with children aged 13 and 14 in Bay of Plenty, Manawatu, Southland and Whanganui, regrets the "ill-considered" wording and apologised.
"In their letter of response they indicated they were echoing the terminology used by some schools, which was not a satisfactory explanation ... they have said this was a lapse of judgment by the employee [responsible]," Ms Casey said.
Associate Professor Ian Lambie from the University of Auckland's school of psychology said the labels highlighted a more serious issue.
"These kids come from families who are disengaged and damaged, and that probably unfortunately reflects the type of kids that they [truancy agencies] see."
The quarterly reports to the ministry from anti-truancy agencies were obtained under the Official Information Act.
Reports from other providers show some performance targets are not being met.
A November update from Waipareira Trust, which works with children in north and west Auckland, shows only 14 per cent of unjustified absence referrals were resolved within 10 days - the ministry's target is 90 per cent.
A spokesman for the trust said cases were deliberately left open to form relationships with students' families. This approach had led to the lowest recidivist truancy rate in the country, he said.
Other agencies have told ministry officials that targets are unachievable.
Ms Casey said the volume of referrals by schools had "taken us all by surprise", and ceded it was "taking some time to bed the service in".
"We think the initial key performance indicators may have been too stringent given the volumes and the resourcing for the service."
Post-Primary Teachers Association president Angela Roberts said cases could be very complex, but the reports showed all was not well.
"What will their point be when they are going to say, 'actually these are no longer teething problems' ... or will they say, 'it's a problem with the contractor' - like they did with Novopay."
Truancy trouble
• Company employed by Ministry of Education categorises truants as "the bullied", "dummies", "brats" and "CYF kids".
• Comes as documents show some performance targets for expensive new truancy service not being met.
• Officials considering whether to scrap those "too stringent" targets.
