Ministry still assessing nationwide survey as problem threatens to cost up to $1.5b.
More schools have been identified as having leaks that are expected to cost up to $1.5 billion to fix.
And that may not be the end of the leaky-schools problem.
The Ministry of Education is yet to finish analysing data from a survey of schools where buildings have been assessed.
Documents released to the Herald under the Official Information Act show a total of 273 primary, intermediate and secondary schools - dozens of them in Auckland - are now listed in ministry documents as having a "defective" or leaky building.
Figures released to the newspaper in November showed 245 schools had been identified as having a defective-building problem.
That figure has gone up by 28 schools, but it appears many more have yet to be officially identified by the ministry.
This year, a letter signed by the general manager of the schools property infrastructure group, Kim Shannon, said schools shown on the current list included those at which repair work had begun.
The list also included schoolsat which repair work had been completed.
Speaking about the national defective-buildings survey carried out last June, Ms Shannon said: "We are still working through the data from our national survey and cannot yet say whether any building in this survey is 'leaky' so these schools have not been included."
The survey resulted in 5500 classrooms or buildings at 1647 schools having to be checked, with 245 schools identified as having a leaky building.
Last year's figures also showed that the estimated cost for the Government to fix damaged buildings in schools would be close to $1.1 billion.
However, the latest estimate isthat the job could cost closer to $1.5 billion.
In a document entitled the "Rejuvenation of Schools' Infrastructure Proposal", dated March 7 this year, the ministry says:
"It is estimated likely to cost between $1 billion and $1.5 billion to repair or replace defective buildings modified between 1995 and 2005 which have weather-tightness issues."
The rest of the report - a 16-page document - is blacked out.
Ms Shannon said the ministry was also representing 24 of those schools which were taking legal action against construction and architecture firms in a bid to win compensation for the repair work.