Prison teachers at the Cessnock Correctional Centre stopped work for an hour on September 5. A similar action by staff at Long Bay Prison in Sydney took place on September 2.
They were protesting job cuts and the outsourcing of New South Wales prison education to staff without formal teaching degrees.
From February, prisoners in NSW will have most of their education delivered by staff from an external training organisation. Most of the prison teachers will be made redundant in December.
The number of qualified teachers in prisons will be cut from 152 to 20, with the gap filled by 60 clerical staff, who will not be required to have a degree. Those positions will be outsourced.