"We were just lucky with my situation that the house was available really, and as a consequence there's been less urgency over space. We've been working with the ministry for the past year and the end of the year (for construction) was seen as the best fit for us."
Mrs Phillips said the new classroom will be built over the Christmas break and the space will be ready for use when the new school year starts in 2017.
"The timing of them putting it in at the end of the year is absolutely perfect for us and the ministry, and their responsiveness has been amazing -- no problems at all."
She said the new classroom would take either Years 2 to 5 or Years 6, 7 and 8.
"That will be decided when we see where the roll and our numbers are sitting at the end of the year."
Wairarapa National Party MP Alastair Scott said the new classroom at Alfredton School was part of a $4 million package for new classrooms in the greater Wellington region that was announced in the Budget last week.
"Here in Wairarapa we will benefit from a new classroom at Alfredton School. Like other parts of the country we are experiencing population growth and this investment will ensure our schools can meet the needs of current and future students.
"We want to make sure we're addressing roll growth and providing flexible spaces to support innovative learning environments for Kiwi children," Mr Scott said.
An $882.5 million package had been announced in the Budget for school property throughout New Zealand, he said, which came on top of nearly $100 million worth of funding announced for school redevelopments in the Wellington area over the past six months.
"A number of schools in the Wellington region have been affected by issues such as leaky buildings and structural issues.
"We've been acting to upgrade these schools and this is the next step in ensuring sufficient capacity and safe and innovative learning environments," he said.