Schools are dealing with at least 550 leak-prone buildings, a decade on from when a programme to fix them was begun.
Back in 2011, the Education Ministry set out to fix 2400 individual buildings constructed between 1994 and 2005, when building rules were particularly lax - for instance, untreated timber was allowed as exterior framing.
At the start of last year, 600 remained to be fixed.
Since then, 100 have been brought up to scratch, but another 53 leaky buildings have been added to the roll.
"The exact number continues to fluctuate as buildings are added or removed," education infrastructure service head Kim Shannon said in a statement.
At 379 of the 550 remaining sites, work is underway, but another 170 buildings have yet to be assessed.
The details on individual projects could not be provided because they were dealt with case by case, the ministry said.
It created its original 2400-strong roll in 2011 after a nationwide assessment.
There was no need to update that assessment now, the ministry said.
This was because other leaky buildings not included in the 1994-2005 weathertightness programme - because they are either older, or newer - were being dealt with under the plans of individual schools, or by ministry-led special projects.
"We have a clear picture of where these buildings are and we have a programme in place to manage them, so we don't need to carry out another national survey," Shannon said.
However, it is not keeping count of what has been fixed this way.
"The ministry does not systematically record or centrally collate which buildings in each of our approximately 2100 schools have been remediated," it said in an Official Information Act request last month.
These records were held at school-level only.
It was too big a job to collate the information, from 15,000 buildings - equal to 35,500 teaching spaces - it said.
"Property management and the delivery of infrastructure projects are part of a school's management responsibility," it added.
The Tomorrow's Schools model that devolves responsibility for property to school boards of trustees has been widely criticised by those caught up in leaky school dramas.
The approach was "not fit for purpose", Lower Hutt lawyer Chris Nicholls said.
He was a board member until recently at Hutt Valley High School as it struggled to get the ministry to address years of leaks, that led to toxic mould, which has forced senior students to study part-time at home this term.
"Our pleas to the ministry were ignored," Nicholls told Education Minister Chris Hipkins in April.
"I would invite the ministry and the minister to consider a review of the suitability of the BOT [build-operate-transfer] model as it relates to school property," he emailed this month.
"I expect the issues at Hutt Valley High are just the tip of the iceberg ... which I suspect is nationwide and systemic."
The ministry is taking over more responsibility for school properties, under a $240m vote in the Budget to create a new division that gives schools more direct support.
Of the 171 buildings still needing to be assessed within the weathertight programme:
- 111 are primarily teaching spaces
- 54 house non-teaching spaces such as gyms, libraries and admin
- 6 buildings are a mix
The ministry said it understood what condition these 171 buildings were in from school 10-year plans and visits.
"We have not been made aware of any weathertightness-related health and safety issues," it said.
Schools should get in touch about any urgent problems.
"We will always provide funding and support to address urgent health and safety matters, or urgent essential infrastructure issues in schools where they arise."
The ministry's track record of responding in the run-up to problems becoming urgent is patchy.