Doctors in the Vanuatu capital, Port Vila, say a viral outbreak has already claimed the lives of three babies.
The acting superintendent of Port Vila Central Hospital, Dr Rose Mary Taun, says the main cause of the deaths was dehydration caused by diarrhoea.
Dr Taun says over the past month there has been an increase in cases of diarrhoea at the outpatient clinic, with the hospital treating, on average, 50 babies with the viral infection each day.
Dr Taun has appealed to parents to take more preventive measures at home.
She is asking them to boil water before use and to take their children to the hospital with the first sign of any infection.