Oranga Tamariki is not saying whether it was involved with the whānau of the toddler who died in Lower Hutt before his death.
Ruthless-Empire Ahipene Wall's death is being treated as a homicide after a postmortem showed he died from blunt force trauma.
Police said on Thursday they were working with Oranga Tamariki as part of their homicide investigation.
In a statement on Friday, Oranga Tamariki said while any child's death was devastating, any questions on Baby Ru's case should be referred to police.
Regional manager Miriama Henderson acknowledged the grief Ru's family will feel.
Meanwhile, Corrections has declined to comment on reports someone living in the house with the toddler was facing violence charges and on a community-based sentence.
Police said they were in contact with three family members who were people of interest in their investigation.
Ruthless-Empire was taken to Hutt Hospital about 10.30am on Sunday in an unresponsive state. Efforts to revive him were unsuccessful.
Police believe his injuries occurred up to 12 hours beforehand.
Detective Inspector Nick Pritchard of Wellington police said they were looking into the background of all the individuals concerned, and were working with Oranga Tamariki and other family members to understand the history of Ru and the family.
"This is a heartbreaking situation and we have an extensive investigation team committed to getting answers about what happened to baby Ru, Pritchard said.
"This level of violence toward a child is difficult to fathom and we will work hard to ensure a thorough investigation is carried out to determine exactly what happened. We urge those who have information about what happened to baby Ru to look deep and do the right thing and tell us what you know."
Community shock
As police continue to piece together the circumstances that led to the death, locals on the streets of Lower Hutt are devastated by the news.
Karen Jones said she was deeply saddened, and her heart went out to the boy's family.
"I feel for the child, what a way to be treated by people that you expect you could trust," she said.
"It's such a betrayal to that child and the child deserves better. It's a shame it wasn't picked up on sooner."
Family violence was a big problem all over New Zealand, Jones said.
"I think it just depends on the stress of the household and the financial side of the household. If they're under a lot of stress, and a lot of it's sometimes because of money, things like that tend to come out, the worst in people comes out. And it's sad, it's really sad."
Another local, Jesse Riwaka agreed, but said family violence seemed to be increasing in Lower Hutt particularly.
She said people who asked for help to leave abusive family situations needed more support to do so.
"They just tell you what to do and not actually be there for you," she said.
"Then [the victims] just end up staying there ... the longer that you stay the harder that it is to leave, and when you have children it's even more hard."
Naomi Shaw, ward councillor for Taita, said locals were "devastated" and the community "reeling".
"How can anyone not be affected by the loss of a child in such circumstances? It's terrible for any community," she told Midday Report.
Government agencies tight-lipped over babies death in Lower Hutt
She said a Givealittle page had been set up "so that the whanau can provide a proper tangi… to assist whanau to farewell their baby with the love and dignity that he deserves".
"Taita was the place that I was born and raised in. It's a very close-knit community of good, decent and caring people who provide great support for each other. It's an incredibly proud community. It's a lovely community spirit that exists and is evident through its schools and community hubs, and lots of active community groups as well."
Shaw did not personally know the boy's family.