Social inclusion is not about "shoehorning every child into a so-called mainstream class" regardless of their needs, Alistair Stewart of the Scottish Secondary Teachers' Association said.
Teachers had a history of trying to provide a curriculum appropriate to children's needs and had been committed to social inclusion long before the Executive had coined the term.
Ministers' approach to inclusion was "at best sterile and at worst dishonest", Mr Stewart said, and would not address the needs of all pupils. The hardest to integrate were those with emotional difficulties who often presented confrontational and disruptive behaviour.
"Whatever the causeof such behaviour, it is clearly profoundly detrimental to the learning needs of the child, his or her class and to the working conditions of all staff in schools. The word stress comes to mind," Mr Stewart said.
The only way to deal with such problems was through intelligent, imaginative and properly funded programmes in school and out.
Jenny Marshall, Educational Institute of Scotland, called for further training for staff and more resources if children with special educational needs were to be fully integrated. "Inadequately done, it can lead to greater exclusion," she warned.
Children she worked with had varied and individual needs.