"We are a small community so you can imagine the impact that has on our school."
Ms Dunn said with the number of teachers dropping they would have to go down to one classroom, which with students ranging in age from 5 to 12 was not ideal.
The school, which is more than 100 years old, has a junior and senior classroom with principal Chris Birch and Jade Lanauze teaching as well as a relief teacher.
"They are small class sizes so the kids get so much help and individual attention, it has all been going really well and I can see the difference in my own children."
The three sisters, Ms Dunn, Emily Hunter and Laura Grady, will make up a quarter of the school role next year when Elsie Dunn, 4, joins her brothers and cousins.
Ms Hunter said they would not send their family anywhere else and some of the traditions they had when they were there were still going strong.
"I can remember the Christmas concert back in our day, there are so many good memories and it's such a unique and special place for kids to grow up."
The school already does a lot of fundraising for everyday upkeep and to fund a teacher as well would be near impossible.
Ms Grady said she did not think they could bake quite enough cakes to keep a teacher on.
Mr Birch said being staffed like a large town school wasn't practical but as soon as the roll was back up to 26 they could claim back their teaching resources.
For more information about the school visit: http://www.kereru.school.nz.