Big disparities are emerging between schools in some of the regions expected to suffer significant roll decline over the next 28 years, principals say.
Education Ministry documents say big drops that will affect the school network are expected in Whanganui, Hawke's Bay, Gisborne, Manawatu, Tasman and West Coast.
The decline is forecast to happen over the next 28 years and the ministry says it is not a pressing problem as it plans for 85 percent occupancy of schools and the six regions are, as a group, at 82 percent.
But some of the regions are worse off than others.
In the Whanganui region, occupancy is at 72 percent, with 7458 children where there is space for 10,374 - not counting classrooms provided by boards of trustees rather than by the ministry.
The ministry says Statistics New Zealand's medium projection indicated Whanganui region rolls would fall by a further 1600 over the next 28 years taking occupancy to just 56 percent.
The principal of Wanganui Intermediate School, Charles Oliver, said there were already too many schools for the city's population.
"There is still exactly the same network of schools as there was in the seventies and eighties but the school population in many cases is under half per schools. I know schools in our city where there used to be 400 pupils, they're down to below 200 pupils now."
"From where I'm sitting, [the Ministry of Education] seems to be just sitting back and they're waiting for the community to say 'oh, we want to have a talk about this'. But really I think that the ministry should be being a little bit more proactive."
Mr Oliver said the ministry could not expect local communities to ask for help, because they could not see the bigger picture of how the region's schools were being affected by falling rolls.
The ministry's head of sector enablement and support, Katrina Casey, said there was not an urgent problem.
"In the Wanganui area, spare capacity isn't currently a pressing issue. Families have a good choice of schools for their children to go to, and they appreciate that.
"We'll continue to keep schools in that area briefed on what the long term trends are for the area, and encourage them to begin conversations about what that might mean for them"
In Gisborne there is room for 11,135 children in the district's schools, but in July only 9248 were enrolled - a shortfall of 1887 children or 17 percent.
That was close to the ministry's goal of 85 percent occupancy, but Gisborne Primary Principals Association president Paul Sadler said some schools were booming while others were struggling.
"Within the city there's some schools that are around say 500, 550, and there are schools in the city that are, from what I'm hearing, around 30 to 50.
"Some of these smaller schools they have a lot of empty classrooms."
But Mr Sadler said he did not want to see schools closed or merged.
"There possibly needs to be a little bit of reallocation of property resources. I wouldn't want to encourage any schools to close, but some of them just need to be smaller. Then those who are slightly bigger have available propety resources to be able to maintain and provide a quality learning and teaching environment."
In Manawatu excluding Palmerston North, school rolls have fallen faster than Statistics New Zealand's medium forecasts and by July this year were at just 4359 children - even lower than the nadir of 4688 they were expected to reach in 28 years.
However, the ministry said those roll numbers were what it would expect.
Manawatu Principals Association president David Reardon said schools in rural areas were worst affected.
He said such schools were important for their local communities, and they should be allowed to continue.
"The feeling among principals and these communities is while we can provide a high quality of education, why wouldn't we," he said.
But Mr Reardon said if schools started to struggle, they needed to decide if they should close.
"It's important that they are able to continue on. If it gets to the point of schools finding it difficult to govern, in fact to form a board of trustees, then perhaps if they're able to make that decision along with the ministry's support, then that would be a good way forward."
In Hawke's Bay, schools have capacity for 34,519 children, but there were only 28,720 by the middle of the year, a shortfall of 5799 or 16 percent.
Statistics New Zealand's medium forecast indicated the region's roll could fall further and reach 24,803 by 2043.
President of the Hawke's Bay Primary Principals Association Mike Bain said some rural schools were smaller than in the past but he suspected the predicted fall in rolls might be avoided.
He said he had noticed more people moving to the region in recent months.
West Coast's schools had 4539 children in July, 1472 or 24 percent fewer than their capacity of 6011. Statistics New Zealand's medium forecasts showed such a low roll was not expected until 2038.
But the president of the West Coast Primary Principals Association, Bevan Clark, said the population appeared to be stabilising after several years of decline driven by factors including coal mine closures.
He said rolls were growing at several schools including his own, Blaketown School, because of an increase in the number of five-year-olds and because new families had moved into the area.
Mr Clark said West Coast schools did not expect closures or mergers in the region, because they were spread too far apart for that to be logical.
Tasman had room for 8599 students in its schools, but there were only 7789 and that could fall to 7078 by 2043.
The Education Ministry's head of sector enablement and support, Katrina Casey, said it used statistics from the Census, school enrolment data and other local information such as household occupancy rates to plan for communities' schooling needs.
She said it worked closely with schools and communities when planning schooling provision.
"There are a number of things we do to help schools manage rolls, including introducing new enrolment schemes, amending existing schemes or removing them. We can also work with the school to change the space they have, including bringing in roll growth classrooms where necessary."