The cost of fixing the buildings will not be known until a $22 million investigation announced in last year's Budget is completed.
The investigation is expected to take all of 2011 because every school which was built, or had work done on it, after 1994 has to be thoroughly examined.
Until then, Education Minister Anne Tolley was relying on a 2009 study of 200 Auckland schools, which predicted it would cost $1.2 billion to fix permanent buildings and about $300 million to replace relocatable classrooms which were leaking.
Mrs Tolley has admitted she has no idea where the estimated $1.5 billion will come from.
She planned to talk to Finance Minister Bill English in the hope some money could be allocated in the next Budget.
Mrs Tolley also suggested schools could use money set aside for other property work on leak repairs instead.
"We are trying to work it in sensibly with work that is already happening at schools, and we may have to talk to schools about their five and 10-year plans and this would take precedence over that in the case of schools we have to seriously rebuild.
"There's lots of discussions to have with the sector, with schools themselves - but with the financing of it, it is not going to be easy."
Principals Federation president Peter Simpson said it would be disappointing if schools had to use property money to fund repair work.
"It's not the schools' fault that there was regulation that allowed untreated timber to be used for framing that's created this problem."
He said the ministry had been pushing in recent years to modernise classrooms, and money for that was allocated in five-to-10-year plans.
"At the end of the day, you can't have the building collapse on you because it's a leaky building, but [reallocating money] just puts creating that modern learning environment for the kids back even more, through no fault of the school."
Mrs Tolley said the ministry was taking legal action against some contractors and "exploring all avenues to recoup the funding" where possible.
However, the ministry was in the same position as many home owners who had leaky homes in that many of the companies at fault no longer existed, she said.
As a result, the ministry was unable to release the names of schools on the list of defective buildings because it was still establishing the extent and nature of problems at each school.
A Ministry of Education spokesman said the issues might have a bearing on subsequent legal proceedings.
"The ministry needs to be sure about the legal position in respect of these issues before it identifies schools."
• Additional reporting by the NZ Herald
