Dame Naida Glavish has renewed calls for the resignation of Oranga Tamariki chief executive Grainne Moss.
A damning investigation by Newsroom citing multiple anonymous sources has claimed the culture at the Ministry can be toxic and staff do not always put children first.
Dame Naida led the Māori inquiry into Oranga Tamariki this year, and said the claims in the latest investigation reflected many of the stories whānau had revealed in her inquiry.
"I think they are absolutely viable, I'm surprised it's taken so long to come out. It had to come out," she said.
"There are many [stories] and these have come from staff of Oranga Tamariki who have been told to shut down, stand up and leave. This is shocking behaviour."
She said if the Ministry was headed by Māori, it would have had to face far harsher consequences.
"If this was a Māori organisation it would have got shut down a long time ago ... how many children's commissioners reports do they really need?"
Dame Tariana Turia also led calls for Moss and Children's Minister Tracey Martin both to be removed after a damning report by the Children's commissioner.
Mothers talked for the commissioner's report spoke about having information kept from them, experiencing threats and coercion, not having confidentiality respected, and being lied to.
Dame Naida said the chief executive of the Ministry needed to go.
"I would like to see, in the first instance, the CEO dismissed on the spot, out of there... and then of course appoint a commissioner of Oranga Tamariki while we restructure it with iwi input into what it might look like from the lens of Māori given that there are so many Māori children [taken from families and placed in state care]."
Children's Minister Tracey Martin declined to be interviewed, but her office said she was taking time to look at the concerns and get more information from the Ministry.
Martin had previously claimed she had never been asked to do anything about Dame Naida's report into the organisation, something Glavish said was absolutely appalling.
Oranga Tamariki also declined to comment.