The chief inspector of the Social Services Inspectorate, Sir Herbert Laming, said that, in the past, care had too often been "haphazard and inconsistent" and this must be altered.
Recent inspections of the quality of care provided by social services departments have highlighted "areas of serious concern" about services for children.
Sir Herbert's annual report into social services, published yesterday, says that a number of "worrying themes" have emerged from recent inspections of social services, including "poor practice and deficient management".
Sir Herbert said that social services departments often did not have systematic ways of dealing with problems and taking decisions. "It was often not possible to see why social services had intervened, what they hoped to achieve and how they would know whether the situation had improved or deteriorated. This is unacceptable.
"It shows that the quality of work with children and families is too often haphazard and inconsistent," concludes the report.
The report notes that demands placed on social services departments have become more complex. The strategy must therefore promote joint working, develop clear, strong management practice and aim to deliver good quality and economic services.
"This means that there needs to be good information to allow people to make more informed choices. This does not happen as often as it should," says the report.
Social Services - Facing the Future is available from the Stationery Office, price pounds 20.