Some of those were going to be much larger than first thought, and the ministry did not want to rush into them and repeat "the mistakes of the past".
"We want to take the opportunity to do something that is going to last for generations - and to ensure fairness," Ms Kaye said.
"The challenge has been the scale of what we expected to find is a lot higher [than first thought]."
Ms Kaye said that after a nationwide property assessment which began in 2012, it was believed 25 to 30 schools would need major redevelopment - because of leaky buildings, old stock or roll growth or a combination of all three.
Of those, 14 had been signed off at a cost of $360 million, and the rest were being prioritised nationally, with "four or five" to be approved by the end of the year.
However, as the assessments were finalised, other schools with major issues had come to light, Ms Kaye said, so the number needing huge cash injections was likely to rise. Figures were expected within the next month.
The Government had allocated $1.3 billion over 10 years for modernising schools, with $300 million extra specifically to cover the worst cases, she said.
Ms Kaye understood the frustration of schools around communication.
"From what I can tell they want certainty around dates. And I think that's absolutely fair." She said she would visit the schools to ensure there was better clarity.
The minister said there was absolutely no reason why any of the schools should be unable to access funds for short-term repairs.
"There should be no board which feels like it can't fix health and safety issues.
"I would be concerned if the ministry didn't have a short- and long-term plan to make sure schools had resources to fix those," she said.
The minister emphasised the funding allocation would be fair and done according to a national priority list.
The Weekend Herald has asked to see a list of schools requiring extensive rebuilds.
So far only those where air testing is under way - 15 schools nationally - has been released.