Letters obtained by the Wanganui Chronicle show a group of parents, believed to involve 11 of the 19 kids' parents, wrote a letter to the board outlining their frustration with the decision to allow the teacher to bring her baby to class.
"Several of our group have made attempts to reach an amicable solution over this situation and feel that the discussions have not improved outcomes for our children," the letter read.
"As a collective group we notice the impact on our children's learning and are hearing from them that they are finding the baby distracting and this has resulted in them discussing the inability they have to concentrate during these periods.
"At no stage have parents been consulted on this matter or even informed and many have found out about the situation from their children and other parents."
The letter also stated several of the parents were considering moving their kids to other schools because of the school's refusal to change anything.
The Board of Trustees stated it was aware of a potential petition from parents in a newsletter sent home with students.
"It has come to our attention that an unofficial petition regarding the baby in class has been circulating - this is incredibly upsetting. The Board of Trustees' official position is that they do not support this. This has been done without agreement and support of the Board and the Board will not consider the results of it."
The acting chair of the Board, Rob Crawley, said the school had actually received a lot of positive feedback about its 'holisitc' approach to teaching.
In the same newsletter the Board outlined why a relief teacher was needed.
It said the usual teacher was undertaking a reading recovery course and would be doing it until the end of the year. The Board was proud of the success of the reading programme that gave struggling students the chance to learn one-on-one.
The Board also said it was lucky to get the relief teacher it did - someone who was experienced and highly recommended.
"Getting a teacher who was willing to drive out for two hours everyday was very lucky. As part of this agreement [the teacher] brings her baby into the class for two hours and she is in a backpack the entire time. This agreement is until the end of 2018."
There's been mixed reactions to news of the baby in the classroom with a number of people voicing their support.
"I have worked in two schools where teachers have brought their baby to class. It was an awesome opportunity to show kids that babies aren't dolls. It never affected the teaching ability of either teacher," Kim Lewis said.
"I think it's a great idea," said Daphne Buckland.
"So those parents need to grow up and leave her alone. Especially when her baby is sleeping so it's awesome to show the kids ... I'm sorry but if one of my kids teacher had baby and came to school I'd be fine with it."
Others have been less supportive of the idea, such as Auckland woman, Kay.
"I am appalled! P.C. gone mad! Is this not a breach of Health and Safety. What if one of the children hurt the child?"
"No, any other job the mother has to put baby in day-care, this should be no different," said Lenny Ellwood.