Watch the Oranga Tamariki CEO fronting here:
The video posted this week on the Newsroom website showed a young person being surrounded by staff, tackled, restrained and held in a headlock at one of the ministry's care and protection facilities.
Since then, some staff have been stood down and Children's Minister Kelvin Davis admitted the system was broken.
The agency's chief executive, Sir Wira Gardiner, said the leaked video was one of the reasons that led to the decision to close down Te Oranga, "... including preliminary investigations, I want to know what happened, why it happened and why our processes didn't work and a range of other questions."