Khyra Ishaq, who died in May 2008, was known to social services
The children's social care department in Birmingham has been criticised as not "fit for purpose" in a report.
A lack of senior managers was a "major risk" and sickness rate among social workers was above 20%, the city council's scrutiny committee found.
The inquiry came after Ofsted criticised care of children at risk. In the past four years eight children known to social services have died.
The council accepted the findings but an MP branded the report a "whitewash".
Khalid Mahmood, Labour MP for Birmingham Perry Barr, said it just highlighted problems which were already known.
'Not comfortable reading'
Government inspectors found weaknesses in the care offered to children at risk of serious physical or sexual abuse in December.
After the report was commissioned, it emerged at least eight children known to social workers had died in Birmingham in the past four years.
Councillor Len Clark: "There are systemic weaknesses in the service"
The latest report, Who Cares? Protecting Children and Improving Children's Social Care, found the current model of service delivery was "patently not working" and added that urgent investment was needed.
Councillor Len Clark, chair of the scrutiny inquiry, said: "Many of the findings of this children's social care inquiry will not make comfortable reading for the council. This was not the intent.
"But if we are to make sustainable progress and not just short-term fixes, we must address the underlying issues identified in our report. This must be the city council's top priority."
But Mr Mahmood told BBC News the report was an "absolute whitewash".
By Mark Worthington, BBC News
Birmingham is home to a quarter of a million children. The city council says it has a higher proportion of young people than any other European city.
Caseloads for social workers are high compared to other authorities and, following the Baby Peter case in Haringey, social workers have been dealing with a substantial increase in referrals.
It means a social care provider with a history of underperformance is increasingly overstretched.
In the last four years, at least eight children who were known to social services have died in Birmingham.
The scrutiny report says the city's problems are "systemic and deeply ingrained" and that failure to tackle the issues will mean the most vulnerable will pay a heavy price.
But it also says that many of the failings which need improvement are national issues.
It seems that while the problems in children's social care may be more obvious in Birmingham, the failings are widespread.
"I don't think it is worth the paper it is written on," he said.
"They have just highlighted issues that are already known.
"This has been hyped as a great report but it isn't - it's an absolute whitewash."
In the report, concern was raised that child referrals were screened by "inexperienced staff" with insufficient management oversight.
The report uncovered "systematic and deeply ingrained" problems which needed urgent action as well as long-term solutions to fix.
In particular, the scrutiny committee said the time social workers spent with the children and families who needed them was severely limited.
The report blamed this on time spent writing records, a high number of case loads, a high number of vacancies and sickness absences.
Members of the inquiry committee also said they were "shocked and dismayed" at the standard of accommodation at some of the council's care homes and called for urgent investment. Other key recommendations included more money for staff training and development and the assessment and development of managers.
The city's social services are under a notice of improvement which will be assessed in February.
Among the cases the inquiry focused on was that of seven-year-old Khyra Ishaq, from Handsworth, who was allegedly starved to death.
Her mother and stepfather, who have denied killing her, are due to stand trial for her murder next year.
The death of Baby Peter sparked a nationwide review of care standards
Birmingham City Council said it accepted the report findings and was already making improvements in some areas.
Councillor Mike Whitby, council leader, said the authority was focused on putting the changes in place.
Cabinet member for children, young people and families, councillor Les Lawrence said: "There is no quick fix to the problems highlighted, some of which affect all councils nationally, such as the recruitment and retention of social workers.
"However, I am committed to doing everything in my power to ensure we provide the best possible care to the children and young people of this city."
Ofsted inspectors had criticised Birmingham's Safeguarding Children Board after finding the level of care offered to children at risk of serious abuse was "inadequate".
That criticism came after the death of Baby Peter in Haringey, north London, in August 2007, which led to an urgent review of children's services across the country.
The 17-month-old boy died after sustaining more than 50 injuries, despite having been seen by child support professionals 60 times.
The country-wide review highlighted weaknesses at six authorities, including Birmingham.
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