"We feel that it's destroying a wonderful school and it is a real threat to a community.
"However, we acknowledge that the minister has conceded that disrupting the pupils mid-year is not in their best interests."
Today's announcement comes after initial plans for the merger were delayed last year, when Phillipstown successfully challenged Ms Parata's decision in the High Court to shut it.
In October, Justice John Fogarty ruled the decision to close Phillipstown and merge it with Woolston was unlawful, after Phillipstown launched a judicial review into the consultation process for the merger.
He said in his decision Ms Parata had inadvertently not consulted to the standard required by the law on the merger.
Mr Simpson said things had been better this time round.
"I do acknowledge that as a result of proving in court that it was an illegal and invalid decision, there have been some improvements.
"I'm anxious for that process to be completely changed so that no other school would ever go through what this community and school has gone through."
While the school knew today's outcome was a likely one, it was still hard to swallow, Mr Simpson said.
"It wasn't a surprise, we're just hugely disappointed.
"We certainly had it in our scope that it could go against us, and there were several signs that indicated to us that our voice and the facts had not been taken into account as seriously as we had hoped."
Ms Parata said in a statement "fresh consideration" of the merger proposal had resulted in a new decision to merge the two schools.
A surplus of places for primary school students in the "local school network" as well as small roll numbers at Phillipstown and significant earthquake and other property related problems at both schools supported the merger, she said.
"Investing in one merged school gives us the opportunity to provide kids from Woolston and Phillipstown with the very latest and best in modern technology and resources."
The Woolston School site will be significantly redeveloped to provide new modern learning environments at an estimated cost of $11.8 million, she said.
"I have been open to the possibilities promoted by the Board of Phillipstown School on behalf of its parents and students.
"I took into account the submission of Woolston School on behalf of its community. I weighed up the fresh information together with analysis and advice from the Ministry," Ms Parata said.
Labour has promised it would allow Phillipstown school to stay open for at least two years, if it leads the next Government.
It would hold a review after two years, Associate Education spokeswoman Megan Woods said.
She said the decision to merge the school into Woolston had been decided without any real evidence that it was best for the community, the teachers, parents or students.
"A Labour Government would grant the school and the community's request to allow the school to remain open, reviewing it once it had looked at population projections and other pertinent information," she said.
Green education spokeswoman Catherine Delahunty said Ms Parata's refusal to budge on her closure plans was "a tragedy for the children who had fought so desperately for their school to remain open".
"This is about Hekia Parata trying to save face after a litany of back-downs, U-turns and policy failures, but it has come at the expense of hundreds of little children and their families."
