A three-year-old boy was forced to eat a cigarette butt by his Child, Youth and Family (CYF) guardians.
Despite continued complaints, the boy and his brother were left with the Christchurch guardian family for five years.
CYF has begun an investigation into the caregivers, and no more children will be placed in their care until it is completed.
The boys were placed in the guardians' care in 2006.
Their mother, who approached The Press, has made a sworn affidavit to the Family Court in Christchurch in a bid to end the guardianship order.
She said she approached CYF for help in 2004 because of her "drug use" and "transient lifestyle" and a violent relationship with the children's father.
The affidavit refers to several CYF reports on the children.
In 2007, CYF was told one of the boys picked up a cigarette butt, put it in his mouth and spat it out again.
He was then taken inside the house and made to eat the cigarette butt and allegedly told: "If it's good enough for you to do it outside, it's good enough to do it inside. Go on, chew it."
The foster mother told CYF investigators she made the child eat the cigarette butt as he often picked things up and put them in his mouth.
The CYF investigator said the foster mother did not do it to punish the boy but to attempt to change his behaviour.
CYF was told the house was a "DIY bombshell", with the play area covered with debris and nails.
An investigator found the backyard was "not safe for any child to be playing in".
Another allegation of ongoing verbal and physical abuse towards the boy's brother was deemed to be unfounded.
In May 2010, a case report noted the children were "suffering alleged ongoing physical and emotional abuse by the caregivers".
It said the notifications of ongoing abuse were continuous, came from different agencies and could not be "assumed to be malicious". The children needed a new long-term home, the report said.
Two months earlier, the guardians told CYF workers looking into concerns about smacking that the children "do not get bashed" but got "a tap on the hand". They were told this was not a "good idea" by CYF as "it could open them up to accusations".
In October this year, the children were removed from the guardians' care.
CYF southern regional director Kelly Anderson said yesterday an investigation had started into allegations against the caregivers, "particularly around the way in which they have managed the boys' behaviour".
"Until that is complete, no children will be placed with this couple," she said. The boys were placed with the caregivers with the agreement of the family as a result of their mother being unable to provide care for them, she said.
"We have worked with the family over time to address concerns about parenting and how they were managing the boys' behaviour; for example, by requiring the couple to undertake parenting courses, further caregiver training and use of respite care," Anderson said.
- The Press