The Association of Secondary Teachers Ireland has said teachers do not have the resources to implement proposed changes to the Junior Certificate cycle.
ASTI General Secretary Pat King said talks today with the Department of Education will be the first real honest dialogue on the Junior Cycle changes.
The meeting follows a commitment made to the ASTI during the recent talks on the Haddington Road Agreement.
Speaking on RTÉ's Morning Ireland, Mr King said the union had engaged in consultations with every school in Ireland and got responses from about 10,000 teachers.
He said teachers are very concerned that schools are not prepared and said that 50% of principals say they do not have the capacity to deal with the changes.
Mr King said the changes in English are being phased-in from next September.
But he said the one-day training being provided to teachers for the new approach is totally inadequate.
Mr King said the ASTI wants reform, but that it has to be organised properly with teachers receiving the proper training.
He said: "We want reform, but we want it to work well. Children get one chance to go through the school system ... it's got to be right.
"We are very concerned that schools are not prepared."