In what has been described as one of the worst instances of child abuse seen in Australia, 12 children ranging in age from five to 16 years old have been permanently removed from an extended family in south-west NSW, where they were living on a farm in primitive conditions in what appears to be an incestuous community.

In the children's court in September, Judge Peter Johnstone ruled that the children, known by pseudonyms to protect their identity, should be permanently removed from the four mothers involved.

He said there was evidence of "intergenerational incest" and that the mothers' refusal to acknowledge their own traumatic past meant they could not protect their children from continuing sexual abuse.

A few weeks ago, two more children were removed from a fifth mother from the same family in Victoria after she admitted to social workers that her brother was the father of her children.