Gordon Smith, their president, says that during the McCrone discussions which led to the teachers' agreement, "there was not a lot of input from primary headteachers into the changes that we are having to manage".
Mr Smith adds: "I am not disagreeing with them but the practicalities are very, very difficult.
"What we are looking for physically is a seat at the table - we want to be there when changes are being discussed. The agreement was between the Government and the Educational Institute of Scoltand and the EIS do not represent all primary heads. There are a number of major issues affecting our members that we feel need further discussion."
He concluded: "The EIS has done an excellent job for its members and we applaud it for that. Whether it has done an excellent job for Scottish education has still to be proved."