The Education Review Office has found widespread deficiencies at childcare centres looking after very young children.
The ERO has just completed an eight -part series of reports advising parents on what to look for in early education providers.
It says it has concerns about aspects of compliance in about 50 percent of the 74 early childhood centres it monitored.
It says half of all under two-year-olds in childcare are at centres that fall short of official standards in some way.
With home-based childcare, one-third do not meet the required standards.
ERO manager for early childcare, Di Anderson, says specific concerns included inadequate supervision of sleeping children and hazard and emergency management systems.
She says officials observed that staff in some centres were not as attentive as they could have been.
Industry bodies reaction
The Early Childhood Council says the ERO report is very limited.
The chief executive, Dr Sarah Farquhar, says the ERO only looked at some centres and its report provides a very limited snapshot.
But the Childcare Association says the report is helpful.
Its chief executive, Nancy Bell, says the report reveals some centres were group caring for children's feeding and toileting needs, instead of catering to individual needs, in order to save time.
She says this is because the current regulation calls for a teacher to care for up to five children at a time, but she hopes this issue can be resolved by using a ratio of one teacher to three children.