"In a way, we provide our own truancy service," Mr Kersten said.
When parents took children out of school for family holidays, requests were approved or not, depending on the deemed educational benefit.
The Attendance in New Zealand Schools 2012 survey measured student attendance over a week in June at 2166 schools. It showed absence rates nationwide had been dropping in recent years and sat at 9.6 per cent last year.
Secondary Principals' Association president Tom Parsons said truancy was a major problem, with absent pupils missing out on vital learning. However, some truancy was condoned by parents, with pupils missing school for family holidays or to look after younger siblings.
"It is unreasonable ... for the mum and dad to expect the teacher to prepare individual lessons for that student that's going to be sitting on the beach in Bali or being a caddy for dad as he plays golf in Noosa," he said.
Absences were highest on days either side of the weekend, with 10 per cent of students absent on a Monday and 11.3 per cent on a Friday.
"Every day a student is not at school is a day they are not learning ... patterns of non-attendance can place students at risk of poor achievement and early drop-out, thus compromising outcomes in life across a range of social and economic measures," the report stated.
Primary and intermediate schools had similar absence rates of about 7.5 per cent. Rates were higher at secondary schools.
Justified absences such as legitimate sick days were similar across all deciles, but high decile schools had lower unjustified absence rates. Low decile schools also had higher rates of frequent truants.
Maori and Pasifika students had twice the rate of unjustified absence of other students, the report found.
Gisborne had the highest total absence rate at 12.7 per cent, while the Otago and Tasman regions had the lowest at 8.3 per cent.
Principal Youth Court Judge Andrew Becroft said up to 70 per cent of youth offenders were not engaged with school.