Labour Party education spokesman Chris Hipkins said the decision to keep the school open was the right one.
"It's just a shame it took a court ruling, relentless community work and a major dose of negative press to bring the minister round.
"Planning to close Salisbury School was a clear breach of the rules. It was another example of an inattentive minister who is out of her depth."
The Public Service Association (PSA) said the decision to keep the school open was a hard-fought victory but one which came at a cost.
"This year-long period of uncertainty has meant that about a third of Salisbury's staff have left, taking with them valuable specialist experience and expertise which is very difficult to replace," said PSA national secretary Brenda Pilott.
"A lot of time, stress and uncertainty could have been saved if the government had listened to the concerns of students, families and staff from the outset."