The number of school suspensions after attacks on teachers in Northern Ireland more than doubled in two years.
There were 243 suspensions and expulsions for physical assaults in 2004-05 compared with 614 in the last academic year, according to figures from the Department of Education.
NASUWT regional secretary Seamus Searson said teachers are now more likely to report abuse.
"There is a tendency that the pupils don`t know where the barriers are and they push and push until something happens," he said.
"We attribute the increase to people reporting them now. All the unions are saying the same thing to their members, that these things need to be reported and not just brushed under the carpet."
He said the department had produced a teacher abuse survey encouraging people to record the events as assaults. However he claimed some principals are keen to avoid this as it affects the reputation of the school.
Alliance Party assembly member Trevor Lunn obtained the information via a written question.
"I am shocked by these figures. The figures had remained pretty static for four years but jumped almost three-fold last year. We need an explanation of why these statistics have shot through the roof," he said.
"There was clearly a problem during that year and I would urge the minister Caitriona Ruane to investigate whether this was just a more stringent crackdown by schools on attacks or if there actually was an increase in attacks on teaching staff," he added.
© Press Association