Updated 7.49am: The Education Minister is defending her decision to approve a charter school, which is now on 28 days notice to improve.

Labour has criticised Hekia Parata for overruling advice from her own Ministry, which was against Te Pumanawa o te Wairua school in Northland.

But Ms Parata is confident the right decision was made.

"A range of advice was taken into account, including that this is in an area of longstanding underachievement."

However the NZEI says charter schools are a waste of money, and there's no benefit to them.

Former NZEI president Judith Nowotarski says the real concerns are around children's education and support networks.

"What is of real benefit is to fund schools appropriately so they can deal with students and meet all their needs." 

Judith Nowotarski says the school was ill-equipped from the start.

"Our concern is what happens to the children? They've been caught in between all of this, what happens to their learning now?"

The school has 28 days to come up with a plan to lift the quality of its education.

About $1.5 million has been spent on the charter school, and the Trust operating Te Pumanawa o te Wairua School in Northland will face a special audit.

Hekia Parata is standing by her decision to allow the school to open.

"I'm satisfied with the risks that were taken and the circumstances of the submission at the time, but over the period the school has been in operation the consistency of the concern has led to action."