The GTC last week launched a framework for professional recognition and registration that sets out the skills, knowledge and experience teachers will have to gather before they can move sector or switch subject.
Tom Hamilton, the GTC's director of education policy, said: "While encouraging greater flexibility, the framework also gives the necessary assurance that the CPD teachers have undertaken is sufficient to meet the challenges of teaching different subjects or in different areas."
The framework is backed by the local authorities, the unions, universities and the Scottish Executive. Those who apply to move must hold a full GTC registration and have taught for at least two years. They will be awarded a certificate of approval for five years once they enhance their skills through continuing professional development.
Primary teachers who want to move into secondary can opt to teach only in S1-S2, or raise their academic qualifications.