An Australian study has for the first time found a link between flat head syndrome and developmental delays in children.

Babies with flat head syndrome may be at heightened risk of developmental delays, a study has found.

A review of 19 research papers conducted by The George Institute for Global Health and the University of Sydney found delays in motor skills, language and cognition were detected in infants as young as six months with plagiocephaly or flat head.

Problems with sitting up and crawling, followed by delays in language - like understanding one's name - were most commonly reported and many of the delays remained for up to three years.

Associate professor Alexandra Martiniuk, who led the study, says this is the first review to systematically say flat head is linked to developmental delays.

While there was variability amongst the studies, the average proportion of children with flat head affected by some kind of developmental delay - beyond what is typically expected - was between 10 to 25 per cent, said Prof Martiniuk.

Other studies showed children with flat head have two to 10 times the risk of having a developmental delay.

The study does not suggest plagiocephaly led to the delays, it simply shows a link, Prof Martiniuk noted.

It does however highlight the need for early and prompt assessment and intervention.

"It is essential doctors, nurses and midwives monitor infants with flat head to ensure they receive appropriate assessment, early intervention and follow-up for developmental delays, Prof Martiniuk said.

The number of children with positional plagiocephaly has risen significantly in recent years, in part due to SIDS guidelines which began in 1992, which recommend placing babies on their backs to sleep.

Flat head can occur if the baby consistently holds his or her head a particular way when lying and causes the baby's head to have a flat spot.

Parents should always follow the SIDS guidelines, which are effective in preventing sudden infant death but also need to make sure babies get enough tummy time while awake, say experts.

Senior physiotherapist Angela Serong from the Royal Children's Hospital Melbourne says five minutes a day of tummy time is not enough to prevent flat head.

"Throughout the day the newborn needs to spend enough time on their tummy to develop the ability to lift and turn their head to clear their airway," Ms Serong previously told AAP.