The Australian Early Development Index, released last week, found higher-than-average rates of "developmentally vulnerable" prep children in suburbs of Clayton, Oakleigh South, Ashwood, Chadstone, Notting Hill and Glen Waverley.

The index compared more than 261,000 children across Australia on five measures: physical health and wellbeing, social competence, emotional maturity, language and cognitive skills, and communication skills and general knowledge.

Dr Anne Kennedy, a senior education lecturer at Monash University, said it was significant that in many of the south-east's problem suburbs, high numbers of children were not attending preschool.

She was not surprised that many of these suburbs were low-income, high-unemployment areas, but said the problems could be fixed.

"We need to get children to preschool, family day care or child care. If there are any developmental problems, we can get them early."

She also called for more hubs that clustered preschools with family health, job training and counselling services. Such hubs would

save money down the track, she said.

Many of the south-east's problem suburbs, also highly populated with new migrants, showed high numbers of prep children lagging in communication skills.

Dr Kennedy said it was important new migrant children maintained their first language rather than skipping straight to English. Good early-childhood teachers would ensure this took place, she said.

"When it comes to learning languages, they have to first be competent at their first language.

"They can develop all their concepts in that language and then they pick up English quickly. It could be, too, that refugee migrant families may not be literate in their first languages."

Children's Minister Maxine Morand noted that children receiving high-quality early childhood services had a better chance of making a successful transition to school.

She said Victoria had the country's second-highest preschool attendance rate at more than 95per cent and the most prep children "on track" with their development.

"Data such as this gives governments, early-childhood professionals and families even more information about what supports are needed and where."