Child Youth and Family has been forced to admit it didn't intervene in a case of severe child neglect because it lost the family.
CYF won't say how many times it assessed the seriously malnourished children before sending them back to their parents.
This incident however is far from isolated, with thousands of abused or neglected children are sent back into abusive homes.
Four children - the youngest just seven months - lived a Lower Hutt home with their young parents. They were severely neglected, malnourished, riddled with scabies and lice in a house with barely any food and lots of alcohol.
Social Development Minister Paula Bennett says it was a family CYF knew all about.
"I think that they've worked with them intensively in the past."
On January 4, the children, along with five others, were taken by police during a party at the house and that night they were placed with a family friend.
Three days later CYF checked on them and they were gone.
"They [CYF] then spent the next three days with police looking for those children," Ms Bennett says.
After that period of searching they were found back with their parents.
Labour's social development spokeswoman Jacinda Ardern says CYF should have known about the seriousness of the case if they worked extensively with the family.
"I would've expected them to know about the seriousness of this case and the extreme neglect that was occurring. These kids simply shouldn't have been in this home."
When asked why CYF did not intervene earlier, Ms Bennett replied, "Child Youth and Family didn't know they were there."
CYF won't say how long it had been monitoring the family, but this case is not unusual.
Over the past five years 17,000 children were assessed more than once by CYF and found to be abused or neglected each time - 154 abused or neglected children were assessed more than five times and sent back into abusive homes.
"That means CYF knowing about kids who are being abused and then it happening again," Ms Ardern says.
The parents have since pleaded guilty to four charges of neglect and the children are in CYF care. As for CYF, Ms Bennett has ordered a report into the assessments and why these children weren't rescued sooner.