Survivor advocate Louise Nicholas, who complained about being sexually abused by three police officers who were acquitted in 2007, said she was "gutted" to hear the new allegations.
"I'm 100 per cent confident that things have changed for the better for our communities, but I'm not dumb. I always know that there will be those idiots, those rogues, that will let our communities and the public and themselves down," she said.
"I know Natalie. I know that she would have been absolutely thorough in her thesis. It highlights the need to help our young women and be there for them."
Ms Thorburn, 25, said a 2002 study found 194 youngsters under 18 who were known by social services to have had sex for money. Prostitution is legal for adults but it is illegal to pay anyone under age 18 for sex.
"We expect that there would be a whole lot more than that who were not known by social services, I would say ... in the hundreds."
She said the children and their families were disconnected from mainstream services and their sex work and associated hard drug use were not picked up even though five of them were still at school at the time.
Seven of the eight grew up in "chaotic" families with "extreme economic deprivation". Only one still had both parents at home.
"There was one who had quite a 'normal' life, was attending a decile 10 school and was achieving really highly, but was going out all night to do sex work and then coming home and putting on her school uniform," Ms Thorburn said. "I don't think her parents knew."
In her thesis, she said a 14-year-old girl "regularly absconded from her residential placement while in the care of Child, Youth and Family (CYF), who would report it to the police. On several occasions this was followed by two uniformed male police officers having sex with her in exchange for money.
"She snuck out of a supervised home and police officers would be waiting down the road to take turns having sex with her in exchange for money," she told the Weekend Herald.
In the other case involving police, she wrote: "A police officer offered to disregard the employment of an under-age sex worker in exchange for oral sex.
"She spoke about having a police officer find her on the street and insist on her giving him sexual favours in exchange for him not putting her back in CYF care," Ms Thorburn said.
In the CYF case, a 15-year-old girl "was being driven somewhere by a CYF social worker who sexually assaulted her when he stopped at a traffic light".
Ms Thorburn said the ethical conditions of her thesis meant that she interviewed all the children and young people anonymously so she did not know their real names and could not report their allegations to police. The participants contacted her by text in response to a flyer which she distributed widely, and received a $40 payment for being interviewed.
"They nominated a false name and a place and time to meet," she said.
However, she briefed a detective in Counties-Manukau Police about her findings this week in advance of its publication yesterday.
A police spokesman said; "We are currently working to gather more information so that we can make a more detailed assessment before considering the next steps."
A CYF spokesman said police should be called in any situation where children were in immediate danger.
"The researcher cites ethics as the reason she cannot report these matters to police. I would question her reasons for then raising them with the media without ... evidence," he said.
Ms Thorburn said her thesis was not intended to accuse any individuals of crimes.
"I'm not investigating the proof behind these statements, but rather using them to inform service developments for social workers and other professions," she said. "I feel that it is ethical to publicise the issue, as community awareness is one of the ways highlighted in the study for these situations to improve."
Alleged offences
• Two police officers took turns to pay for sex with a 14-year-old girl who was in child welfare care.
• Another police officer made a girl have oral sex with him in exchange for him not returning her to child welfare care.
• A child welfare officer sexually assaulted a 15-year-old girl while stopped at traffic lights in a car.
• Police are investigating all the allegations.
