CHANGES to adoption laws and shifting social trends have led to a sharp reduction in the number of children being adopted in Australia over the past 25 years.
A report, released on Friday by the Australian Institute of Health and Welfare, showed the total number of finalised adoptions had fallen by 78% between 1987/88 and the past financial year.
There were 333 finalised adoptions in 2011/12, the lowest annual number on record and a 13% fall from the previous year's low of 384.
There has also been an 84% drop in the number of Australian children being adopted in the past quarter of a century - down from 1183 in 1987/88 to 183 in 2011/12 - although this number has been stable for the past decade.
AIHW spokesman Tim Beard said the long-term fall in adoption numbers could be attributed to legislative changes, such as a greater use of alternative legal orders, as well as changing social attitudes.
The number of intercountry adoptions fell by 52% over the past 25 years, from 308 to 149.
Further, the report shows processing times for overseas adoptions have risen to more than four-and-a-half years on average.
It is the first time the AIHW has published processing times in these reports.
The average time from the approval of an applicant to the placement of a child rose from 37 months in 2007-08 to 56 months in 2011-12.
"This rise can be attributed to the increased time taken by countries of origin to allocate children after receiving files from Australia - up from 19 months in 2007-08 to 30 months in 2011-12," Mr Beard said.
"Processing times are affected by factors such as the number and characteristics of children in need of adoption, the number of applications received and the resources of the overseas authority.
"These are all factors outside the control of Australian authorities. Australian ... authorities have maintained or improved the time taken to complete the aspects of intercountry adoption they are responsible for."
Mr Beard said for the first time since 1998/99, there were more finalised adoptions of Australian children than children from overseas.