A Whanganui principal says a $330 million underspend on a Government-funded education initiative can be put down to doubts about the way it would work.
Charles Oliver, principal of Whanganui Intermediate School, says Investing in Educational Success (IES) - launched as a flagship scheme in 2014 - is a great concept.
"The problem is not with the idea - it's a very good one - but schools who sign up to it will be locked in for a three-year term."
The IES policy was promoted a dramatic shift in the way schools operated - from a competitive model to one of collaboration and partnership.
Schools are encouraged to cluster together in Communities of Learning in groups of about 10 schools, sharing information, expertise and ideas, and creating a "pathway" for students from primary through to secondary.
"In Whanganui, we have had a lot of discussions between primary, intermediate, secondary and early childhood providers to see how this might work," Mr Oliver said.
"There are a number of things we are concerned about.
"The main concerns are that there is not provision to improve the quality of teachers' abilities which will lead to better outcomes for learners, and that one principal in a group of schools will lead the group and receive a substantial increase in salary."
The Government pledged $359 million to IES over the first four years, and $155 million a year after that, when it announced the scheme in 2014.
However, only $26 million of that pot has been allocated in the first three years of the initiative - that's just 7 per cent of the total.
With only one financial year left, there is still $333 million un-spent.
Mr Oliver said in Whanganui voluntary collaborations had been formed in a "try before you buy" approach because there was no data or history of the concept.
"The idea of one principal being substantially rewarded while others get no incentive is inherently unfair.
"We have suggested to the ministry that the money could be spread around, but they have not been willing to listen."
He said Whanganui schools would embrace the concept but they feared getting "stuck" for three years in a collaboration that was not workable.
"Schools are used to being autonomous so the collaborative approach needs to be carefully thought through," he said.
Labour's education spokesman Chris Hipkins said the under-spend went to the heart of the problem with IES - that teachers were sceptical about jumping into another Government scheme aimed at raising achievement.
"It would be fair to say that they've been underwhelmed by the whole concept and as a result [the Ministry] can't give the money away," he said.
Although Mr Hipkins has described the scheme as "flawed" due to lack of consultation, he said Labour would not scrap IES if they become the government after the next election.