Primary school rolls would drop by 5 per cent or 27,520 children between 2022 and 2032.
“This is driven by a lower number of births, a reduction in primary-aged net migration and larger birth cohorts which peaked in 2008 and 2010 transitioning from primary school to secondary school,” the forecast said.
Secondary school rolls would increase 5 per cent or 15,017 students between 2022 and 2025 before declining by almost 6 per cent or 17,000 students by 2032.
The forecast said homeschooling enrolments were likely to exceed 12,000 within two years and then decline slightly.
Enrolments in specialist schools for children with disabilities were expected to increase by 25 per cent or 1561 children to 7708 by 2032.
The forecast said specialist school enrolments had been growing at about 6 per cent per year for the past five years.
It showed school rolls peaked last year at 824,075, dropped to 817,369 this year, and were expected to grow again to 822,231 next year.
Statistics New Zealand data suggested the biggest proportional drops in the number of children under the age of 15 could happen in Kawerau, Gisborne, and Porirua.
It showed the number of children under the age of 15 could fall by about 20,000 in Auckland and 5000 in Wellington by 2032.