The application was not opposed by the Crown.
A summary said the woman subjected the children to punches and slaps in the face, pulled and shaved-off their hair, and had two of them shave each other's eyebrows as forms of punishment.
In one particular case recalled by one of the victims by dragged by her ear into a cold shower after asking about letters believed to have been sent by her parents.
As a teenager one was slapped in the face when sent home from school where she had been caught with cannabis, and later punched in the face for seeing a boy with whom she was told not to associate.
Defence counsel Leo Lafferty, standing-in for Scott Jefferson said the woman was "extremely remorseful" and did not "resile" from her offending, the substance of which he said was the use of force at times of stress in trying to cope with matters of discipline.
She had several references which highlighted her contribution in the community, and there was a "considerable degree of healing" going on with the family as it dealt with the matters that had arisen, he said.
The Judge said that while the offences were "disturbing," it was obvious the woman had a lot of involvement in the community had a lot of "good attributes".
She clearly had problems managing the children, and had herself "described the situation as a mess," and accepted she should have reacted differently, Judge Mackintosh said.
Oranga Tamariki regional manager East Coast Kellie Blyth said she commended "the young people for their bravery in speaking up".
"All children deserve to belong in families who love and care for them, and in this case, this didn't happen," she said.
She said that while the offending predated Oranga Tamariki, it was "still important to consider the circumstances and what we can learn from it".
"We acknowledge the important role that grandparents play as caregivers for many of the children in the care of Oranga Tamariki," she said.
"Last year, we established a dedicated Caregiver Support Service whose sole focus is finding and supporting the right caregivers for children and young people in care," she said.
"We have Caregiver Support Plans in place for over 93 per cent of our caregivers to ensure that they are getting the right support to meet the needs of the children in their care."
"Oranga Tamariki is committed to ensuring that all children and young persons in New Zealand are safe and we are saddened that this has happened for these young people," she said.