Greens co-leader James Shaw has apologised for backing an $11.7 million grant to an exclusive private school saying it "was an error of judgment".
He now personally wants the grant given to the Green School as a loan so it's paid back in full.
But Shaw said the mistake wasn't one that would warrant his resignation as co-leader, though conceded the controversy might risk the Green Party making it back into Parliament.
"As a politician, admitting you were wrong is one of the hardest things to do.
"We're expected to be infallible. So much so that we can forget that people prefer their leaders to be honest and compassionate. Becoming a Minister means being willing to question your decisions in public and, if necessary, correct them.
Shaw's apology comes after days of criticism from schools, unions, the Greens' own voter bases and the Opposition over the fact the private Taranaki school, which charges up to $40,000 a year in fees for international students, got almost $12 million.
The money came from the Government's $3 billion pot for "shovel ready" infrastructure which would stimulate the economy.
The Green School promised the expansion project would create 200 jobs and deliver $43 million to Taranaki.
Treasury didn't support the project, though Shaw refused to go into details on their advice but said it had been given a high rating by the Infrastructure Reference Group.
But Shaw pushed hard for the project, telling other ministers he would withhold sign-off of all the other projects in the $3 billion fund if Green School wasn't approved, Newshub reported.
Shaw said today he'd pushed for the project to be funded because it was an opportunity to support a sustainable construction project and was advocated by New Plymouth Mayor Neil Holdom.
It was Shaw alone who pushed for the funding because it was a Budgetary decision, he couldn't consult other MPs from his party.
But the public response to the funding became apparent very quickly, said Shaw.
"The decision I made to support this project was an error of judgement, for which I apologise.
"If I was making the same decision again, I would not support this project."
Since the announcement about the funding on Wednesday, Shaw met school groups and unions and read feedback from teachers, principals and parents. He said he'd taken time to reflect on their concerns and to act on them.
Shaw said while ministers could not interfere in commercial negotiations, his personal preference is the $11.7 million be provided as a loan so it is repaid in full.
The Green School also had not fared well from the outrage, he said.
"Their reputation has taken a battering."
He understood representatives from the school were in conversations with the Crown.
Shaw said the Greens put together an "exclusions" list for shovel ready projects, like motorways, which Shaw said would lock in a high-carbon future, but it was an oversight to not apply a wider lens to the project.
Shaw said every dollar of the $3 billion fund was spent to create jobs and one of the sectors most at risk from the downturn was infrastructure and construction.
He said this had knock-on effects for the local community.
But it was "a fair question" to ask why the money was going to a private construction project when so many public schools were run down and mouldy.
Last year the Government committed almost $400 million to every state school for property improvements but it was apparent this wasn't getting out the door fast enough, said Shaw.
He said the Greens' decades-long commitment to public education hadn't changed.
Co-leader Marama Davidson said the Greens would have to continue to fight to make sure they were above the 5 per cent threshold to get back into Parliament after the election.
Davidson said this was a mistake which they apologise for and they are trying to find a solution.
Yesterday, the chairman of the Taranaki Secondary Schools Principals' Association (TSSPA), Martin Chamberlain, published an open letter to Education Minister Chris Hipkins.