Rates of substantiated child abuse and neglect have risen in Australia, with very young children the most likely to be the victim, according to a new study conducted by the Australian Institute of Health and Welfare (AIHW).

The Child protection 2011-12 report found that over the past 12 months,  the number of children who were the subject of substantiated abuse increased from 31,500 to 37,800-a rate of 7.4 per 1,000 children.

In 2011-12, children aged under one year were most likely to be the subject of a substantiation, with a rate of 13.2 per 1,000 children in this age group, up from 12 per 1,000 in 2010-11.

"In contrast, older children, aged 15-17, were least likely to be the subject of a substantiation, with a rate of 3.2 per 1,000 children in 2011-12," AIHW spokesman Tim Beard said.

At 30 June 2012, there were nearly 40,000 children in out-of-home care. Most (90%) were on care and protection orders.

The time a child has spent in out-of-home care varied-while 38% of children in out-of-home care had been in a continuous placement for five or more years, a further 19% had been in their current placement for less than 12 months.  

Across Australia, the vast majority (93%) of children in out-of-home care were placed in home-based care such as with foster carers or relatives/kin. This follows a similar pattern to that observed in previous years.