A mother used false identities, a secret bank account and a "well-organised network" to kidnap her daughters and hide from authorities for more than four years, police have alleged in court documents.

In affidavits tendered to the Supreme Court in Brisbane, police alleged a north Queensland mother went to great lengths to remain in hiding for that time, and had a list of associates helping her do so.

The mother, 45, and her primary school-aged daughters, who cannot be named for legal reasons, were reported missing in April 2014 but were recently found in the New South Wales town of Taree after an extensive nationwide search.

Police alleged the girls were living with their father when they were taken by their mother after being dropped off at a Townsville school.

They said the mother had made unsubstantiated claims that the girls were being sexually abused by their father.

After she took the girls out of Townsville without their father's knowledge, she and her daughters moved around the country in secret, the affidavits alleged.

According to the documents, the girls said they had lived in northern Western Australia, Perth, as well as Grafton and Taree in NSW.

The mother was charged with child stealing and the two girls were returned to their father.

Network provided 'information, money and accommodation'

Police said the mother handed a female associate a sealed envelope in the months before the trio's disappearance with financial details and a list of phone numbers "in the event she went missing or was in trouble".

Investigators said this associate opened a bank account under her own name and allowed the mother to use it.

Police alleged that when they eventually located the mother, she was living in a property rent-free and was in possession of four Medicare cards in other names, along with cash and medication.

Townsville-based Detective Inspector Dave Miles said she had tried to disguise the girls' identities and had gone as far as changing their birthdays.

"Despite the assertions of [the mother] that she lived off the grid, the reality is that she existed within an environment of false identification and multiple personas, along with a myriad of technological products to assist her with maintaining her contact," Inspector Miles wrote in one affidavit.

Police also alleged the mother was helped by a network of associates, including a doctor and a man who set up a website and Facebook page to champion the woman's cause.

In another affidavit, Detective Senior Constable Kate Ringberg wrote: "The associated network assists in the provision of information, finances, accommodation and the means necessary to continue to elude authorities".

Senior Constable Ringberg said the network had "taken it upon themselves to publicly defame the children's father as a child sex offender when there is no evidence to support that fact".

Earlier this month, the mother was granted bail on strict conditions, despite police opposing her release, fearing she would use her network of contacts to take the children and return to hiding.

The mother is due to appear in the Townsville Magistrates Court on July 16.

Grandmother used 'same network', police allege

A woman accused of stealing her grandson was released under strict bail conditions. ( ABC News )

In a separate case, a north Queensland woman accused of stealing her seven-year-old grandson and relocating him to New South Wales was released on bail on Tuesday.

Police told the court the Townsville woman, 56, used the same "network" to get advice on how to conceal her and her child's whereabouts.

The woman's lawyer denied the claim and had earlier told the Brisbane Magistrates Court the woman "doesn't know who those people are".

The woman's bail conditions include having no contact with the boy's father, wearing a GPS tracker and remaining 30 kilometres from Townsville at all times.