The General Secretary of the Association of Secondary School Teachers has said there is "no way" his members will give up the additional allowances they earn on top of their basic salary.
New figures show that both primary and secondary school teachers received more than half a billion euro in allowances last year.
They can earn extra money for things like teaching through Irish, teaching in a Gaeltacht area and doing yard supervision duties.
Fine Gael TD Jim Daly has urged teachers to give up some of these allowances, to preserve services in schools.
But General Secretary of the ASTI, Pat King, has said that is "not going to happen" as it is part of their contract and therefore cannot be revoked.
Mr King said: "Teachers don't get these additional payments for doing nothing."