Parents of pupils at St Mary's Diocesan School in Drogheda, Co Louth, may stand in the general election if they do not get a written commitment from the current candidates that there will be an extension to the school.
The council and teachers have called a public meeting for tonight to which all the candidates have been invited.
The allboys school was built to accommodate 200 pupils. It got the first half of an extension in 1994 which allowed for an additional 300 pupils. However the current enrolment is 710 and 140 are expected to enrol in September.
The parents' council has raised £300,000 towards the total cost of £1.5 million.