Roll growth has pushed the school network to its limits in some regions this year, with some having to use their halls as make-shift classrooms.
Ministry of Education figures show there are more students than classroom space in state and state integrated schools in Tauranga, while Hamilton, Selwyn, Waimakariri, Ashburton, Kapiti and Queenstown-Lakes are getting close to that point.
The ministry is building new rooms and new schools in those areas but principals say it should be acting faster.
It aimed for 85 percent occupancy of schools and nationally the figure is 89 percent, not counting rooms built by schools from their own funds rather than by the ministry.
Tauranga exceeded its capacity half-way through this year, and at least two schools in the city are using their halls as classrooms.
Tahatai Coast School principal Ian Leckie said his school was close to capacity and the district was growing so rapidly the ministry was reviewing the enrolment schemes of schools in the area for the second time in five years.
More Tauranga schools were introducing enrolment zones or shrinking existing zones in order to keep a check on their student numbers.
The growth was happening fast but the ministry could have acted quicker, he said.
"Certainly the ministry is looking at it. Are they moving quickly? I think it's fair to say they're not.
"We have heard that there is a plan in the background but no one's seen it, so we're looking forward to early next year when we have invited the ministry to come and share their growth plan for the whole of Tauranga and how education needs are going to be met."
Ministry taking action
Ministry head of sector enablement and support Katrina Casey said it was taking action.
Funding for 29 new teaching spaces was approved for Tauranga schools this year, while the two schools using their halls as classrooms would get new buildings in 2016, and the third stage of a new high school recently constructed in Papamoa would be completed.
The ministry also had new rooms and schools planned in areas where schools were at 97 percent of capacity or more, such as Hamilton, Ashburton, Kapiti, Selwyn, Waimakariri, Wellington and Queenstown-Lakes.
"In 2015, we approved funding for at least five new classrooms in Ashburton, eight in Queenstown-Lakes, 13 in Selwyn, one in Kapiti Coast and two in Waimakariri," Ms Casey said.
A new primary school opened in Flagstaff, Hamilton at the start of 2015 with a capacity for 400 students and the new Rototuna Junior High School in Hamilton would open at the beginning of 2016 with capacity for 1200 students. Rototuna Senior High School will open in 2017, which would provide a further 800 places for Year 11 to 13 students. A third primary school, for 700 students, was planned for 2019.
"In Queenstown-Lakes we have recently opened Shotover Primary School. We are also discussing future schooling options with the Queenstown and Wanaka communities.
"In Selwyn, a new secondary school will open in 2017 and work is well underway on a new primary school in the south of Rolleston, which will open for Term one in 2017.
"In Wellington we are putting in additional teaching spaces at schools across the city to address areas of demand."
Hard to predict numbers
Principals Federation president Denise Torrey said it has proved very difficult to predict population movement in Canterbury, so capacity issues in Selwyn, Waimakariri and Ashburton might have been difficult to avoid.
But the ministry should have been able to get ahead of growth in other areas, she said.
"The ministry needs to have a better system of collecting data about population trends and shifts so that they can actually move much faster. And I'm not sure why building buildings is so slow. They need to get on to this much faster than they are doing."
Children should not have to be schooled in halls or crowded classrooms, she said.
But Ms Casey said the ministry monitored roll growth carefully.
"We have been and continue to be very active in managing capacity over a very long period of time - this is not something that occurs over a few months, it literally needs to be done over a period of years and it needs to be done right across the country.
"We monitor school rolls across local networks, and work to ensure we make the most effective use of existing property. This can be a challenge in areas where populations are growing rapidly."