It's about workload, says NASUWT
More industrial action is planned for Manx schools this week.
Members of NASUWT, the teaching union, have been asked not to cover staff absences or help with after school activities.
It's to try and force government back to the negotiating table over a row about pension pay and working conditions.
Damien McNulty is the national executive member for NASUWT.
He spoke to Ewan Gawne: