Babies aged four to six months sleep an average of 14 hours a day, which drops to 10 hours by the age of nine years, a snapshot of children's sleep patterns has revealed.

A study by researchers at the Murdoch Childrens Research Institute looked at the sleep patterns of 10,000 Australian children, including how many hours they slept each day, how often they woke during the night, and their bedtimes.

Lead researcher Anna Price said the aim was to provide accurate, age-specific data on children's sleep, which researchers will analyse to determine whether there are links to mental and physical health.

21 year old mother of two boys, Denise Bros, with Jack Primrose, 2 1/2 and 10 month old Harry Primrose at their home in Franklin.

SLEEP EASY: Denise Bros says she was grateful for some sleep instruction for her sons Harry Primrose, 10 months, and Jack Primrose, 2, pictured at their home in Franklin. Photo: Graham Tidy

''Whether a child is getting enough sleep or how much sleep a child needs is a major concern to many parents,'' Dr Price said. ''In this study we found there is a wide range in 'normal' child sleep from four months to nine years old.''

The study, published in the Archives of Disease in Childhood, found sleep time over a 24-hour period fell from an average peak of 14 hours for four- to six-month-olds to 10 hours for nine-year-olds. This is mainly due to progressively later bedtimes, shifting from 8pm for babies to 9pm for older children. Older children also sleep less during the day and wake less during the night.

But Dr Price said there was wide variation in sleep patterns even within each age group. Babies aged four to six months had from 10 hours to 18 hours' sleep over a 24-hour period, while nine-year-olds had between six and 14 hours' sleep.

''This is what is happening with children's sleep now, and the next step is to find out if there is an optimal amount of sleep that is best for children's behaviour and health,'' she said.

Dr Price said sleep problems were most common with young babies, and typically involved them having trouble getting to sleep and waking frequently during the night. Problems often occurred because children had become accustomed to having a parent with them as they fell asleep, and needed help learning to fall asleep on their own.

Canberra mother Denise Bros said her 2½-year-old son Jack slept between 11 and 12 hours a night with an afternoon nap of four hours, while her 10-month-old Harry slept similar hours but woke between two and eight times a night.

''Currently we don't have a set bedtime for them; we usually put them to bed after dinner around 6.30pm or 7pm. This will change when they are old enough to attend preschool in a couple of years.''

Ms Bros said children's sleeping and eating were two of the major topics of conversation among mums at her playgroup. She was grateful for some sleep instruction early on.

''We prepared for our kids by attending the Queen Elizabeth II Family Centre. They bring you along to stay for four nights and help monitor your baby's needs. Each time your baby wakes during the night you need to alert one of the nurses and they teach you about learning what your baby wants and how to put it back down to rest afterwards.''

with Adam White