New research has raised questions about something that's common practice in the majority of childcare centres.
The Sleep in Early Childhood Research group found children exposed to more than an hour of forced napping at centres slept worse at night, even when they started school a year later.
Lead researcher Dr Sally Staton, from the Queensland University of Technology, said childcare providers needed to question whether mandatory nap times were appropriate.
"Certainly we're not suggesting that sleep time is not an important component or providing for sleep is not an important component," she said.
"But certainly (they need to be) thinking about whether mandatory sleep times, in particular really long mandatory sleep times, are actually the most appropriate way of meeting sleep needs, particularly for these pre-school aged children where their needs are so diverse."
Dr Staton said another recent study found children had grown out of napping by the time they were three or four years old.
Federal legislation calls for centres to cater to the individual sleep needs of all their students but there is limited guidance about what exactly that means.
In practice, Dr Staton's previous research found about 80 per cent of Queensland centres enforced mandatory nap times, where children were forced to lie on their sleeping mat without access to any other activities.
Those sleep periods could be as long as two and a half hours but were about an hour on average.
But the study, to be published in the US-based Journal of Developmental and Behavioral Pediatrics next month, found even in long mandatory nap periods only half of the children actually slept.
The QUT research fellow's study of 168 children across 130 services, which were selected from a larger representative study, found children exposed to mandatory napping slept an average of 24 minutes less at night.
"I guess what's particularly concerning is when we got to the second year of the study, so once the children were in school, they were getting less sleep overall," Dr Staton said.
"So their total sleep was less, probably because now they weren't napping and the amount of sleep they were getting was actually dropping below what we could consider the normal range for children of that age group."
Australian Childcare Alliance CEO Gwynn Bridge disputed the 80 per cent figure, saying most centres gave children options to cater for their individual needs.
"Most of them are encouraged to read a book or they can lay next to their friend and have a chat," she said.
"A lot in the older groups aren't even putting mats out now.
"[For] the children who want to sleep and the ones the educators know will sleep mats will be offered, but it's certainly not the case where every child must sleep for an hour and a half."
- Brisbane Times