Struggling families who keep their children from school to mind younger siblings or sick parents are believed to be behind alarming attendance figures.
According to Ministry of Education figures, nearly a third of students failed to attend school regularly last year. Students who attended more than 90 per cent of school time were considered by the ministry to have attended regularly.
Figures showed 77.1 per cent of students at decile 10 schools attended more than 90 per cent of the time.
That compared to 57.2 per cent of students at decile one schools.
Deciles are a measure of the socio-economic position of a school's student community. Decile one schools have the highest proportion of students from low socio-economic communities.
Attendance was the worst among Maori students, with 56.7 per cent attending regularly.
New Zealand Principals' Federation president Iain Taylor said Maori students with attendance issues were likely to be in low decile schools and non-attendance was likely to be parent condoned.
"And that's not because parents are taking their kids on expensive holidays."
The students might be taking care of a sick parent or younger siblings. There might be no food in the house and the student might be ashamed to arrive at school with no breakfast or lunch.
A parent may have been taken away by police or have failed to return home from a night out and the student might have to take responsibility for other family members.
Parents may also be forced to spend the day trying to resolve a financial, food or debt crisis.
"The other reason students may be away is illness," Mr Taylor said. "In the case of low decile school students, there is a higher likelihood that doctor's visits are too expensive and so early preventative medical interventions are not sought.
"Consequently it is more likely that, by the time medical aid is sought, an illness has become serious and likely to take longer to overcome."
Mr Taylor said the principals' federation promoted a broad and rich curriculum so students wanted to be at school.
"Applied or practical learning tends to be more motivating for students and results in higher levels of engagement.
"That is one of the reasons that we oppose narrow assessment measures in just reading, writing and mathematics. We know that students who are at risk of underachievement are the very students who need the broader curriculum."
Rotorua Lakes High School principal Bruce Walker agreed many school absences were condoned by parent who thought a day off here and there was fine - but those days added up.
He said year 12 girls were often kept off school to babysit or help with family functions. That wasn't beneficial to academic success and pursuing the career they wanted.
Poverty could also play a role in absences.
"If you don't have a clothes dryer so you can't dry the uniform... there's all sorts of reasons like that."
Students from a dysfunctional family may also not be woken up for school.
"So there are a tonne of different reasons and it's something that families and schools have to work [on] together and it's no use really attacking each other over it."
Students could also be absent if their family decided to take a holiday when fares were cheap. In many cases, it would be a family trip of a lifetime.
Lakes High monitored attendance and sent letters home when a student's attendance dropped below 70 per cent.