Up to 17,000 secondary school teachers will begin strike action today.
ASTI members at around 500 second-level schools will not attend meetings outside of school hours, and won't take on additional duties without pay.
They may also opt out of covering for colleagues absent on school business and won't participate in training for the new Junior Cert.
The Union insists the action should not impact on students.
Pat King is General Secretary of the ASTI
