Some principals believe many youngsters are sent to school early as parents are unable to afford childcare.
Around 1,000 delegates are attending the Irish Primary Principals Network (IPPN) conference, which will be addressed by the Minister for Education Ruairi Quinn later.
Minister Quinn will also be told of the increasing pressure on principals, many of whom teach full-time, combined with their administrative duties in running a school.
Brendan McCabe, President of the Irish Primary Principals Network, said: “Certainly that question of work overload and initiative fatigue (will be raised)”.
He said the issue of whether children are starting school too early needed discussion, as it was a question being debated by principals “whether all children are ready for school at the point when they actually start, or whether they are being forced to start school early because of economic pressures on the parents.”
He said the decision to start a child “too early” could be forced on parents “because of the exorbitant cost of child-minding and the lack of nursery facilities for children”.