Experts have criticized the trend where an increasing number of Aussie preschool girls, as young as six, are transforming into sexualized ‘mini-adults’ by wearing bras, nail polish and lipstick.

Child development experts said young girls were now entering their "tween" years between being a child and a teenager at the tender age of six, which is five years earlier than previously.

Experts said that by age six, girls needed branded clothes, at seven they wanted styled hair, by eight they were beginning diets, at nine they were styling their hair and by early teens were engaging in sex or sending sexually explicit text messages.

In fact, a major department store is selling crop-top style bras for toddlers aged two to three-a move that has sparked outrage from parents.

Professor of Developmental Psychiatry at Monash University Louise Newman said that the alarming trend is taking a heavy psychological toll.

"I've seen children suffering from clinical depression in primary school because they don't feel they are pretty enough or thin enough or able to be popular," The Daily Telegraph quoted Newman as saying.

"The girls are worried they won't get boyfriends, girls have started defining their self worth in terms of themselves as a sex object," he added.

Dr. Joe Tucci, the CEO of the Australian Childhood Foundation, said unprecedented numbers of young children needed psychological help.

Child advocate Julie Gale was outraged to find bras for toddlers on sale at stores including Target.