Principals say high employment and Covid-19 disruption are behind a spike in teenagers leaving school early.
Education Ministry figures showed nearly one-in-five of last year's school leavers was under the age of 17, the highest figure in a decade.
Retention rates were worst in low-decile schools and among Māori students, with a third of Māori school leavers under the age of 17.
In Gisborne, Northland and West Coast, about 30 percent of school leavers were under 17.
The increase in early leavers coincided with lower qualification rates for school leavers.
Almost 13 percent of last year's leavers did not have any NCEA qualification and 21 percent had only level 1.
Te Manihi Tumuaki Northland Principals' Association chair Alec Solomon said some students dropped out of school because of the pandemic, but others had found work.
"We have seen some students leave earlier than we have in the past. Some of those have taken up opportunities for employment, a significant number of those have gone into the trades, there's obviously been a building boom here, and that's really meaningful employment, that's wonderful mahi," he said.
Solomon said schools were trying to re-engage those students who had drifted out of the school system.
However, he warned that this year was even more challenging than last year because of the unpredictable nature of staff and student absences.
He said the most vulnerable students needed to know as soon as possible if changes would be made to the NCEA qualification to mitigate the impact of the pandemic.
In Taranaki, the percentage of early leavers jumped from 18 - 20 percent in most years prior to the pandemic to 26 percent last year.
Spotswood College principal Nicola Ngarewa said schools' connections with young people had suffered because of the pandemic and some found it too hard to return to class.
"Things start to accumulate - the pressure, the habits that they start to form whether its sleeping a little bit longer when they're not at school and then the stress on top of that and the anxiety," she said.
Ngarewa said more teens had left school early because they had jobs.
"They're picking up initially part-time work and that then becomes something more consistent," she said.
"I do have concerns that some of the jobs that they're going to, while they're good for the here and now, do they open up future opportunities and improved quality of living as they get older and I think there's big question marks there."
Ngarewa said ideally young people who found work should be able to continue studying for meaningful qualifications.