The union says "schools are reeling from almost a decade of austerity measures"
The union of Irish secondary school teachers claim that greater independence for school management could lead to further inequality.
The government has issued two reports into further autonomy - which would give individual schools greater control over their budget and other measures.
However, the Association of Secondary Teachers in Ireland (ASTI) is warning that it could lead to schools being run like businesses, and teachers being poached by fee paying schools.
Kieran Christie, General Secretary of the ASTI says things have already been tough for public schools in the past few years, suggesting that many have had to drop subjects.
He also says, "we know that the middle management structures within schools have been essentially downgraded to the point of almost abolishment".
ASTI Vice President, Ed Byrne said, "right now, schools are reeling from almost a decade of austerity measures.
"What parents most need now is not more school autonomy but a system which provides a high quality education to their child regardless of family income, what part of the country or city they live in, or what type of school they attend," he added.