Romahapa School Board of Trustees chairwoman Megan Carey wrote to Minister of Education Nikki Kaye on Tuesday stressing the ''totally unacceptable'' situation the school was in.
The 85 pupils enrolled there pushed the school 220% over capacity, she said.
Staff at the school had reached ''an impasse'' with Ministry of Education representatives, which was ''completely unacceptable to our Board of Trustees and teaching staff''.
Mrs Carey requested some form of temporary classroom to assist as the school was ''operating under extremely crowded conditions'' squeezing four classrooms of children into two teaching spaces.
The situation was ''totally unacceptable'' and would hinder the progress of pupils.
''At present we cannot cater for some [of the pupils'] needs.''
Minister of Education head of Sector Enablement and Support Katrina Casey told the ODT 43% of pupils resided outside of the Romahapa School Zone.
The ministry did not provide teaching spaces for out-of-zone pupils and the school was providing transport for pupils as far as Balclutha.
The school had already implemented an enrolment scheme which would reduce the roll to a more manageable level in time.
In the meantime there was a project in the school's long-term property plan to convert existing staff and resource areas into at least three additional teaching spaces.
The project was expected to cost $100,000 and would be funded by the school's five-year capital funding allocation in 2017/2018, of which there was about $150,000.
School principal Mark Preddy said the school would not be able to convert the spaces until the end of the year. Even then it would only accommodate 60 pupils. The school expected its roll to exceed 80 for at least the next three years.
As to why 43% were from outside the zone, some enrolled while within the zone, but their families had since moved.
As spokeswoman for the ministry said that, until earlier this year, Romahapa School had not implemented an enrolment scheme to help ease capacity pressures.
Changes to the Education Act in May enabled the ministry to put in place an enrolment scheme when a school refused or was slow to do so. This included restricting pupils who were out of the school's zone or catchment.
Mr Preddy said the school had already refused enrolments to pupils since the scheme was implemented.
