Updated at 5:18 pm on 21 August 2015
Education Ministry figures show school truancy rates reached their highest point in a decade last year.
Education Ministry figures show an estimated 79,000 children were absent each day when schools were surveyed during the middle week of June last year, and nearly half of them were wagging.
Principals say social media has made it easier for children to skip classes, and family hardship was contributing to a rise in persistent truancy.
The figures put the truancy rate for 2014 at 4.6 percent - up from 3.9 percent in 2013, and the highest rate for a decade.
Also up was the rate of persistent truancy, rising from 1 to 1.3 percent, despite the introduction of new truancy services in 2013. Persistent truancy is defined as three or more unjustified absences in the week of the attendance survey.
Porirua College principal Suzanne Jungersen said she was not surprised.
"The circumstances of the families which find themselves in the category of persistent truancy are worsening. Families are finding things even more difficult, they're stretched financially, they're stretched in many other ways. I think that's possibly a factor in the increase in that category.
Ms Jungersen said the attendance service in her area had improved, but there was only so much it could do to help the families of persistent truants.
But the Education Ministry's head of sector enablement and support, Katrina Casey, said it was too early to know if the increases were a trend or merely a blip in the statistics.
She said they might have happened because of better reporting by schools, or because more teens were staying at school longer.
"Schools are retaining kids that would have left earlier and we think some of the kids that they're retaining are perhaps not kids that would have be attending on a regular basis. So, inadvertently, a lot of the good things schools are doing may possibly be having an impact on some of these statistics."
PPTA Secondary Principals Council chairperson Allan Vester said there were certainly better, computerised systems for tracking attendance.
And he said schools were taking it more seriously.
"My feeling is there's a scary amount of money that goes out in many schools into the truancy part - looking at the attendance of students, following up with the parents when the students aren't at school. Most schools are spending a significant amount of money on that now - much, much more than we would have in years gone by.
Truancy services have reported that social media is contributing to truancy.
Mr Vester doubted that was about cyberbullying - rather, it made it simpler for teenagers to organise a day off school.
The Ministry's figures showed Gisborne and Northland had the highest rates of unjustified absence at 8.6 and 8.7 percent.
They also showed there was more truancy on Mondays and Fridays than other days, and that Maori and Pasifika children were absent the most.