The prospect of better pay and better support is leading many top public school principals to take up roles with private schools.
Five state school principals have taken top jobs in private schools in the past two years.
Principals can earn from $90,000 to $292,000 a year in the public system, but some principals have reportedly doubled their salary in the private system.
Long Bay College principal Russell Brooke has been appointed principal of Academic Colleges Group's Parnell campus from June 12.
He told Newstalk ZB's Mike Hosking his decision was based on change.
"Someone said 'hey, consider this opportunity', and I looked at it, and the friends that knew me talked about where I was in my life, and I thought 'it's an opportunity, let's go for it'."
Brooke said money is not necessarily the driver behind the change.
"It is relevant. I mean obviously it will help in my retirement and I've got to think about that. Teaching is not well paid in any part of a secondary school."
Jack Boyle, from secondary teacher union PPTA, points out that the public school system is failing to retain the leaders it trains.
"They've done a lot of that learning and development in the state system," he said.
"There's therefore been quite a bit of an investment in terms of resourcing and support.
"You'd need to look at what some of those challenges are that might be causing principals to leave public schools and go into private schools so that we can hang on to them."