Dr Brian Symon, a senior lecturer at the University of Adelaide, says there is clear evidence for the benefits of breastfeeding, "but limited evidence that these benefits are amplified by making it exclusive".
He wants Australian health authorities to rethink recommendations for six months of exclusive breast feeding.
This is because breast milk may not provide enough nutrition for some babies after four months.
The Australian guidelines are in line with World Health Organisation recommendations.
In the lead-up to World Breastfeeding Week from August 1, Dr Symon says he is seeing many young children with sleeping, feeding and weight-gain problems.
"Breastfeeding is extremely important for children's early life, but there is evidence that the emphasis on exclusive breastfeeding in the first six months may be linked to certain health problems," says Dr Symon, who led a two-year self-funded review of research.
"This includes the rapid increase in food allergies among children. Some studies suggest that delaying the introduction of solids is contributing to this problem.
"One of my biggest concerns is the impact that emphasising exclusive breastfeeding has on the mother's confidence, self-esteem and general wellbeing.
"As a clinician working with breastfeeding mothers on a daily basis, it is evident that some women are unable to meet the full energy needs of their child from their own milk.
"Children who do not start receiving complementary solids from four months of age are often hungry, sleepless and upset.
"It's time we revisited the national recommendations to provide the best possible health advice for parents," he says.
It is a worthwhile debate, says Professor Katie Allen, Director of Population Health at the Murdoch Children's Research Institute in Melbourne.
"There may be some babies ready at four to five months. But there is good evidence that introducing solids before four months is probably not helpful.
She says research shows parents introduce solids from four to six months in more than 90 per cent of cases and current National Health and Medical Research Guidelines have been softened to recommend the introduction of solids around six months.
"Our recommendation is that solids should be introduced around five to six months after taking the baby's developmental readiness and the mother's lifestyle and feeding desires into account.