"They are better working with their own folk, who will be critical and who will debate with them, because if they don't, down the line will come the TTA (the Teacher Training Agency) or the inspectorate agencies of the kind they have in England," Mr MacKenzie said.
"The consequences for the profession would be dire."
The GTC was the natural "gatekeeper" to the profession. "Don't allow a few people to hijack the delivery of courses, put in their own third-rate people so that they can control and become the gatekeepers, deciding who is going to become headteachers and taking control of the Scottish education system, " Mr MacKenzie said to warm applause.
Marie Allan, a Scottish Secondary Teachers' Association member, said in-service was a professional entitlement, not a legal requirement. Teachers wanted to develop throughout their careers but they were opposed to mandatory training.
"I want to be able to choose myself what I need and I do not want it imposed on me. Unless you get a body like the GTC involved, there is no way I am going to allow my employers to force me to go to something that is not worth while or third-rate," Ms Allan said.