A secondary teachers' union has accused the Education Minister Ruairí Quinn of opening talks on a second Croke Park deal through the media.
It comes after Mr Quinn told the Sunday Times he wants negotiations for a second agreement to begin in the Autumn.
The deal, which protects pay levels and increments and does not allow compulsory redundancies, has been criticised by Transport Minister Leo Varadkar, among others.
Diarmuid de Paor, the General Secretary of Association of Secondary Teachers in Ireland, has said teachers have given up enough already.
Mr de Paor said: "The well has been gone to a lot, and I am not saying there is nothing, but I am saying that it is going to be hard to find extra productivity.
"But I also want to say that I think it is a pity that the minister is starting negotiations on a second Croke Park deal in public, because I don't think that is the way to do business.
"I don't have a mandate to negiotiate a second Croke Park, obviously if the Government approaches the unions to talk about it, we will talk to them and then we will listen to our members through our democratic structures."