Ed Balls, British secretary of state for children, schools and families, said council officials in the London borough of Haringey allegedly failed to offer adequate protection services to Baby P and his sister despite each being under protective services, The Sunday Times of London reported.
Balls said Saturday the death of Baby P in August 2007 was being investigated to determine what government officials failed to conduct "crucial interventions" with the 17-month-old's family.
"I am angry that crucial interventions to save this little boy were not made," Balls said. "Professionals working with children do a tough job in very difficult communities but I will not hesitate to act on the findings of the investigation."
Specific details on the new allegations regarding Baby P's sister have not been disclosed.
The Times said Baby P's mother and her boyfriend, whose identities were not reported, were convicted in the boy's death from multiple abuse injuries. The couple's lodger, Jason Owen, was also convicted in the case.