Child development services are failing to keep up with WA's baby boom and the 8000 children a year who need extra help, advocacy groups say.
Children and Young People Commissioner Michelle Scott and the WA Council of Social Service say a surge in births means WA needs to expand and better plan services, including health and education, for young children and their parents.
Though figures for last year are not available, WA had a record 32,259 births in 2011, compared with 23,600 in 2002. The number of births in WA has increased 16 per cent in the past five years and 34 per cent since 2001.
Ms Scott said one in four WA children was developmentally vulnerable in at least one area by the time they started school.
"This means more than 8000 children born in 2011 will be disadvantaged in some way by the time they are five unless we act now," she said.
"The health and education prospects of Aboriginal children are even more tenuous, with one in two developmentally vulnerable by the time they start school.
"While there have been recent increased investments, including an additional 100 child community health nurses and more funding for child development services, these measures are only addressing shortages that have arisen over the past 10 to 20 years."
Ms Scott said significant improvements were needed in early childhood health, mental health and education services and parenting programs.
The commissioner said a comprehensive early childhood plan was needed, including a central centre similar to one in South Australia, the Fraser Mustard Centre, set up by the Telethon Institute for Child Health Research and the SA Department for Education and Child Development.
WACOSS chief executive Irina Cattalini urged the setting up of an Office for Early Childhood to co-ordinate services and for more health professionals, such as child health nurses.