A shortage of inspectors in the Dublin area in particular is reportedly leaving pre-schools without adequate monitoring.
That is according to figures obtained by Independent TD Róisín Shortall, who said the Government should be prioritising childcare to ensure children have the best start in life.
The figures show major regional variations in the level of inspections of early childcare facilities.
Speaking on RTÉ's News at One, Deputy Shortall said her information showed that in the West of the country there was a ratio of one inspector to almost 7,000 children.
Meanwhile, the ratio in the East Coast and the North-East was one inspector to 21,000 children in the 0-5 age group.
Tusla, the Child and Family Agency, has said a new national approach and registration process would ensure all services would be inspected every three years.
However, Ms Shortall described this target as "very unambitious".
"I think it's very unambitious to be aiming for an inspection regime where childcare facilities are inspected only once every three years,” she said.
“If we are serious about giving children the best start in life that does mean putting in place the kind of investment that will ensure that the services they receive are good quality services and they will help the children to thrive," she added.
Deputy Shortall also said the childcare system was underfunded, and many facilities in lower socio-economic areas were closing because the model the Government was using was not sustainable.