The classrooms were empty in most secondary schools in the south-east, but in a minority of cases parents declined to take pupils home and classes went ahead.
Mr Sean Hurley, of the ASTI, said boards of management at all schools had written to parents advising them to keep their children at home as they were not in a position to guarantee a safe environment.
Most parents had taken the advice, he said, but those who did not had been telephoned yesterday and given the message a second time. "Some came in and took their children home, but some did not, and in those schools classes went ahead."
The schools where some children were taught included Wexford CBS, but the majority reported that no pupils had turned up.
One school principal in south Tipperary, who asked not to be named, said it was unfortunate that the dispute had reached this stage when there was so little between the two sides. He was concerned that the withdrawal of voluntary supervision was introducing a "work-to-rule mentality" to the teaching profession.
"Teachers have always carried out these duties without fuss, and it would be a major loss to the education system if that changed. But that's the Celtic Tiger, isn't it?" he added.
However, Mr Hurley, the south-east regional representative on the ASTI's national executive, said teachers were resolved to continue pursuing their pay claim.
The Waterford Council of Trade Unions passed a motion at its monthly meeting supporting the ASTI's "legitimate pay claim".
