CYF spoke to Cezar's mother

James Allan Hemana. Photo / Supplied

The mother of Cezar Taylor had been spoken to by Child, Youth and Family shortly before the six-month-old died from non-accidental head injuries.

A new social worker was assigned to her early this month after she moved to Auckland - but there was no follow-up before Cezar was admitted to Starship hospital a week ago with serious head injuries.

He died on Wednesday night from the injuries that were consistent with shaking and a blow to the head.

CYF head Ray Smith said the agency had been involved with the family "a number of times" in recent years. "Tragically, Cezar was admitted to hospital before the next meeting was held," Mr Smith said.

The partner of the boys' mother, James Allan Hemana, 30, has been charged with assaulting Cezar and will appear in the Manukau District Court today.

Hemana was living with Cezar's mother and the child in Mangere East when the injuries occurred. The couple had been together a couple of months.

"It is extremely distressing that a baby has now died as a result of such callous abuse. We are working with the police to assist them in any way possible to get to the bottom of who is accountable for inflicting these terrible injuries," Mr Smith said. CYF would not say how they became involved with the family.

Cezar's two siblings, who are pre-schoolers, were with family members and not their mother when Cezar was fatally injured.

Mr Smith promised CYF would work with the police to help get to the bottom of who was accountable for Cezar's "terrible injuries".

The Office of the Chief Social Worker will conduct a review of CYF involvement of the case. Detective Senior Sergeant Richard Wilkie said Cezar's body would be released to his family today after the completion of a post-mortem examination.