Parents too often condone the absence of their children from school for relatively trivial reasons, the conference was told.
It backed a resolution from Olwen Williams calling for the Assembly to put parents under the same pressure to ensure attendance as schools.
"Absence is more prevalent as children get older and there are feeble excuses from parents," she said. "The government expects schools to perform on attendance statistics, but they can't do it on their own.
"You hear nonsense after nonsense about parents' rights, but not so much about their responsibilities because that's politically inconvenient. The current situation is like having a child of separated parents who divides and rules."
Mrs Williams was backed by Hazel Hayman, a governor from Swansea, and a magistrate. "I don't think parents realise the disservice they do by not sending their child to school," she said.
"As magistrates, we've been criticised when we resort to the final censure, sending a mother to prison.
"I think we could avoid that by having pressure on parents from the Assembly wherever possible. Ninety per cent of children who come before us in court lack educational skills."