The INTO leader, Senator Joe O'Toole, accused the Minister for Education of "wilfully ignoring the immediacy of the crisis in primary school funding and staffing." He also called for legislation to deal with disruptive children.
Mr O'Toole said there was a worse gap between primary and post-primary funding now, in the booming late 1990s, than in the "bad times" of the early 1980s.
The union will today almost certainly pass an emergency motion deploring the Minister's "inadequate response" to the worsening problem of teacher shortages and inadequate funding, and threatening industrial action unless they are tackled.
Mr O'Toole, while praising the Minister's performance in many areas, rejected his assertion that career breaks, job sharing and early retirement were significantly to blame for the shortage of teachers.
He said the number of career breaks was the same or slightly less than five years ago; there were 25 job-sharers among 21,000 primary teachers, and early retirement was running at around 50 people a year.
He attacked the Department of Finance for effectively controlling the level of entry to teacher training colleges.
"They keep getting it wrong," he said. "They let in too many in the 1980s and too few in the 1990s." He warned that there would be a worsening of the teacher supply in the next two years due to a rising birth-rate, increased immigration and more retirements.
Mr O'Toole said discipline was becoming the problem in Irish schools. "It is wrong that schools should be left without a safety net or boundary wall of legal powers or protection in dealing with highly disruptive children.
"Legislation must be put in place giving school authorities the power to exclude dangerously disruptive children from our schools where it is clear that the school cannot include them."
He said the INTO was "prepared to defend the actions of teaching staff and principals who reasonably and professionally decided not to accept a pupil into a class where that would be a threat to the safety or to the constitutional right to primary education of the other pupils in the class."
The INTO leader also warned about the thousands of untrained, unqualified people in charge of pupils.
Schools unable to find qualified teachers were forced to choose between splitting up a class, not admitting pupils or finding some reasonably responsible adult to supervise them in the absence of a teacher.
He pointed out how risky that was. He asked what would happen if a paedophile slipped through the net and got a job. That had happened a few years ago when an Irish-born Australian teacher was employed by a school from an INTO substitutes' list and turned out to be a paedophile.
On that occasion the Department had said it was not its responsibility. Mr O'Toole said that in the future the Department would have to accept some of the responsibility when untrained people were taken on.