The mother of five-year-old Malachi Subecz says "there are no words that can describe the emotions" she's endured over the past year.
Malachi died in Auckland's Starship Hospital last November after being found with injuries a judge said were obtained through abuse considered no less than torture.
The carer who murdered Malachi, 27-year-old Michaela Barriball, was jailed for at least 17 years in June.
Malachi had been placed in the care of Barriball by his imprisoned mother.
The five-year-old's mother said in a statement released by the Department of Corrections she "would not wish" her experience on anyone.
"I’ve made my mistakes, all of which I live with every single day."
Her statement comes after the review of the high-profile case was released on Thursday by former health public servant Dame Karen Poutasi. It follows a separate report by the Chief Ombudsman into Oranga Tamariki's handling of the case, released in October, which found the children's agency's response was "a litany of failures" and did not prioritise Malachi's welfare.
The review found agencies "could have done more" after fears for the child's safety were raised.
Malachi's mother hopes the review ensures "this does not happen to other parents doing a lag who have kids".
She made a plea for those with children: "Do not trust anyone with your kids who aren't family".
"A harsh lesson I’ve learnt in the worst possible way."
The jailed mother thanked people who had "genuinely" supported her and helped her through the "toughest time of my life".
The report painted a sad picture of how Malachi became an "invisible child" within the system.
That was because there were people who "tried to act but were not listened to", those who were "uncertain and did not act" and others who "knew and chose not to act".
"This is not acceptable," the report said. "The settings for the care and protection system we have in place are still not strong enough to ensure children do not slip through the gaps.
The system could have been more 'fail safe' and the settings must be addressed so that it is."
Dame Karen said more steps needed to be taken to ensure Malachi's safety.
"The system has not been designed with layers of safety nets to eliminate gaps."
Dame Karen said one of her 14 key recommendations was to make it mandatory for Oranga Tamariki to vet a proposed carer when a sole parent is taken into custody.
