Green Party co-leader James Shaw is facing criticism from party members for approving nearly $12 million in funding for a privately-owned "green" school in Taranaki.
It flies in the face of the party's policy to not publicly fund private schools.
James Shaw is under mounting pressure, and is urgently working to find a solution before an online meeting with members tonight.
"We have a policy which I had a lot to do with developing over nine years, that we don't fund private schools, but we put our resources, the state's resources into quality public education where it's so badly needed for so many of our young people," Greens' former education spokesperson Catherine Delahunty told Checkpoint.
"Although this project, this money, came out of the Provincial Growth Fund, for infrastructure, schools are infrastructure, and I think that it'd be great if James as minister who made this mistake owned it, and did his best to make sure that the money went to the people that actually need it.
"I feel very strongly about this. Public quality education took a total bashing under the National government and has not yet recovered. They brought in national standards, charter schools and underfunding like we've never seen before.
"As you will have seen in the media today there were teachers in Taranaki very, very upset, and I must say I do feel for them, who have high-needs kids, broken classrooms, mouldy rooms, and for them there's just no logic in Government putting $11 million into expanding a private school which should not be funded by the state."
James Shaw's defence of the funding for the private institution was that it would provide jobs, but Delahunty told Checkpoint the Government could help provide jobs in public education.
"Investing in building programmes for public schools provides exactly the same jobs, and provides exactly the same money into the local community.
"I'm sure now that this issue has arisen that the schools of the Taranaki area could come up with a number of projects.
"I think part of the problem is that the Provincial Growth Fund has been like a lolly scramble, where a group of ministers have got in a room and looked at thousands of competing bids - not the best way to do it.
"And I think that James as minister has become isolated from the party to some degree, in the sense of his instinct didn't tell him that this was never going to fly with the Green Party, and that our policies are never to fund private schools."
Shaw declined to be interviewed on Checkpoint on Friday but in a statement said: "I have discussed the Government's decision to support a 'shovel-ready' construction project at the Green School in Taranaki with the PPTA, NZEI and the Principals' Association.
"I have also received messages from concerned members of the public, seen the commentary on social media and heard from teachers, principals and parents who are disappointed by our decision.
"I have listened to these concerns and I am working to find a solution. However, I cannot say anything more about that right now," Shaw said.