Postgate School will be zoned from next year.
The Whitby decile-four school has been struggling to cope with a growing roll in the past three years, with students housed in the staffroom and library for lessons.
Principal Adam Campbell said the zoning was the Ministry of Education's decision and the school would have to make the best of it.
"We are going through the process now, contacting our families and ensuring that they let us know of siblings that intend to come to the school.
Mr Campbell said he was not certain which areas would be excluded from the zone, but there would be some overlapping with Paremata and Discovery schools.
"It's unfortunate it has happened, especially when you have got to know some families very well, but this is a necessary evil that we have to deal with.
"At the moment you know all the children by name, but if the roll continues to grow the kids become a number and you lose that personal touch."
Zoning would mean the roll could come down to a "comfortable 320", enabling pupils to experience a better classroom environment, he said.
It would also mean teachers would get their staffroom back.
"The kids have adapted well and the families have been great, very supportive."
Postgate's neighbours Discovery, Adventure, Papakowhai, Pauatahanui and Paremata schools are zoned. Tairangi (Waitangirua) and Rangikura (Ascot Park) are not.
Mr Campbell also wanted to pay tribute to the Porirua community for supporting the school's gala on November 17.
More than $20,000 was raised.
- Kapi-Mana News