Betty Colt arrives at court.

Betty Colt arrives at court.

The matriarch of a family from which six children were removed amid allegations of neglect, child abuse and incest has been accused of "masterminding" a plot last year to snatch two of her children back from foster care.

The 48-year-old woman, Betty Colt - a pseudonym as she cannot be named for legal reasons - has been charged with procuring the removal of a child from care and with recruiting a child to carry out or assist in criminal activity.

She has been accused of hiding a mobile phone in the bush behind the foster home and organising to meet the children in a park nearby. Police prosecutor, Sergeant Matt Zalunardo, revealed she intended to take them to South Australia where other members of the family live.

The magistrate, Mary Ryan, has reserved her decision, but queried whether the police had made out the case that the older son had been recruited to effectively kidnap the younger brother, who has been described as having moderate intellectual disabilities.

Describing it as a "dreadful case," she said she nonetheless had to be satisfied that the mother had convinced the son to coerce his younger brother and there was some advantage in it for her.

The prosecutor said it was to Ms Colt's advantage to stop the children co-operating with other investigations.

Ms Colt's lawyer, Phil Carey, said the older son had come up with the plan to run away.

Six of Ms Colt's 13 children were removed into the care of the state last year after they were discovered in June 2012 living among a group of 40 adults and children on an isolated farm an hour and a half from Canberra.

Another six children under 16, also living on the squalid farm were also removed.

The children were undernourished, had terrible dental problems, some were unable to talk intelligibly and were well behind their peers developmentally and some have intellectual disabilities.

Once in care, the children, who range in age from five to 15, told carers they had been sexually abused by siblings and by adults on the farm.

Subsequent genetic testing has revealed that of the 12 children, 11 had closely related or related parents. Ms Colt was living in an incestuous relationship with her brother on the farm. There was also evidence that Ms Colt and her siblings are likely the result of incestuous relations between their parents, who migrated from New Zealand in the 1960s.

In September last year the Children's Court ordered the children be placed in permanent foster care until they turn 18. In doing so the judge, Peter Johnstone, said the case appeared to involve "intergenerational incest" as there was evidence that the four mothers had themselves been the victims of sexual abuse within the family from as young as 12.

But soon after the children were placed in care, Ms Colt devised a plot to get two of her sons back from the foster carers. Ms Colt also faces charges of recruiting her son Bobby (a court appointed name) to commit a criminal act. Ms Colt had secretly given her sons a mobile phone which they kept in a plastic bag in a bush on the foster property.

The extended family, numbering about 40, moved from interstate to NSW in 2009, but it is understood the family may have already come to the attention of child protection services in other states and moved to avoid orders relating to their children.

The NSW Department of Family and Community Services and police finally visited the farm in June 2012 and removed the children the following month after seven risk-of-significant-harm orders. The case has raised questions about the inadequacy of information sharing between state child protection authorities and why authorities let the children slip through the cracks.

Members of the family were also understood to be on Commonwealth benefits, raising further questions about why authorities were unable to track down and protect the children.