Prime Minister John Key's former primary school, Aorangi School in Christchurch, says it will fight the Government's decision to shut it.
The decile-three school, with a roll of about 90, was facing the axe because of a falling roll and costly building replacement work.
Education Minister Anne Tolley announced yesterdaythat it would close in January.
Aorangi School board of trustees chairman Greg Thompson said he was "gutted" by the decision.
The school would immediately launch legal proceedings to overturn the decision, he said.
"[The decision] wasn't unexpected. Once the minister gets on a course of action they will follow it through."
Mr Thompson was told yesterday afternoon, but the school had not had time to tell the parents before the decision was released to the media.
With the end of the school year less than four weeks away, there was not enough time for the students to adequately make the transition to new schools, Mr Thompson said.
Mrs Tolley said the decision to close the school was not an easy one.
"But after considering final submissions from the school and from the Ministry of Education, I believe it is the right one," she said.
Aorangi was a small school that needed major investment in its buildings, the community was served by other nearby schools and it had a falling roll over the past few years, she said.
"I can't justify spending over $2 million on Aorangi's planned replacement building programme, especially in the current economic climate. An independent review by Ernst and Young of the savings associated with the closure has confirmed the costings upon which I've based my decision."
She said the ministry would help Aorangi's current students enrol at new schools and support them through the transition period and into the first term next year.
A change manager will be appointed to support the school, families and students through the process. The proposal to close the school was opposed by the Canterbury Primary Principals' Association and the national Principals' Federation, which said losing Aorangi "would be in breach of the principles of natural justice".
Federation president Ernie Buutveld had said the ministry's original costing data had actually changed several times and an independent review stated that the "errors cast grave doubts on the underlying assumptions and calculations".
