The checks were intended to stop another Baby P tragedy
The leader of a council named as having one of the worst performing children's services in England has said some issues need tackling urgently.
Ofsted's "poor" rating of the service from Leeds City Council was revealed in a review by the Audit Commission.
It comes after a surprise inspection in July which identified some children as having been left "at potential risk of serious harm".
Council leader Richard Brett said the council would make improvements.
The Audit Commission's report is one of 152 assessments of local authorities in England looking at all aspects of public services to create a single snapshot of an area.
Leeds is one of nine authorities to be rated in the worst performing category.
Others include Haringey, the local authority in which Baby Peter died, and Doncaster and Rotherham.
Referring to Leeds, Ofsted said that "while the overall effectiveness of a majority of the local authority's inspected and regulated services and provision are good or better, there are significant weaknesses in areas of social care provision".
It said that "the response to child protection referrals did not meet statutory guidance and did not ensure children were adequately safeguarded, noting a potential risk of significant harm to children and young people".
Ofsted noted that the council had acted swiftly to address the weaknesses.
Mr Brett said: "We accept that there are a number of issues within Leeds children's services that the council and its partners need to tackle urgently.
"However, we believe that it is important our current challenges are seen in the context of the majority of our inspected services, which are good or better.
"We will continue to work closely with the Audit Commission and our partners to bring about the improvements needed to all our services."