The "largest and most challenging" investigation ever undertaken in New Zealand into "horrific and devastating child sexual abuse material" has led to 146 children around the world brought into safety through hundreds of investigations. 

Here in New Zealand there were six children made safe and 46 people arrested, including one man who was a children's sports coach and teacher aide. 

Also arrested was a man who admitted to travelling to South East Asia where he would arrange with parents to sexually exploit their children over cameras later. He denied sexual exploitation while abroad but was likely a "sex tourist", say officials. 

Internationally, the New Zealand-inspired operation was huge and the biggest of its kind to come out of New Zealand. 

It began with a questionable internet link picked up by an electronic service provider in September 2019. 

A Department of Internal Affairs investigator identified about 32gb of files per link including videos described as "some of the most sadistic sexual abuse, rape and torture of infants and children". 

A month later, DIA got account information from the service provider that showed more than 90,000 accounts internationally that had held or traded that set of child abuse imagery. 

Dubbed "Operation H", the information saw DIA's Digital Child Exploitation Team co-ordinate an operation that brought in the FBI, the Australian Federal Police, the Royal Canadian Mounted Police, the National Crime Agency in the UK, Europol and Interpol. 

In a statement, DIA said: "This has been the largest and most challenging online child exploitation operation led out of New Zealand." 

The DIA team is the lead agency of three New Zealand agencies that enforces laws prohibiting child sexual abuse material. Where other nations have developed "centres of excellence", New Zealand shares the job between DIA, police and Customs. 

Hundreds of investigations were launched across the world, DIA said, and work began here with police and Customs to identify offenders in New Zealand from February 2020. 

DIA said 125 New Zealand-based accounts had been linked to the investigation. Internationally, there were 836 cases investigated. 

"Due to the number of user accounts identified and the extreme egregious nature of the child sexual abuse material involved, this is the most significant joint child sexual exploitation operation conducted within New Zealand." 

Digital Child Exploitation Team manager Tim Houston said the global operation was a "major success" in removing environments and networks that sought to exploit children. 

"This operation will have an impact on the global networks that deal in the most horrific and damaging material, and we are extraordinarily proud of the effect it will have on children's lives around the world." 

The team had seized and examined "hundreds of thousands of child abuse material files" which were "some of the most egregious investigators have been exposed to". 

"Many of the children featured in the images and videos were just infants who were exposed to obvious and intentional pain and suffering," said the DIA statement. 

Houston said the type of content - at the extreme end of the spectrum - was the sort that led those who sought it out to physically offend against children. 

"Many people who view material of this kind will go on to physically offend against children, it is imperative that we are able to bring them to justice before they are able to do more damage. 

"This is one of the largest investigations of online child sexual abuse conducted in the department's history." He praised the three-agency approach saying it was "yet another excellent example of cross-agency collaboration in Aotearoa". 

The international scale of the operation was reflected in the statements provided by DIA's media team from law enforcement agencies around the world. 

In the United Kingdom, the National Crime Agency's Child Sexual Abuse Threat deputy director Sarah Blight said 450 people had been arrested, including people working in "positions of trust" such as primary schools and nurseries. 

Others arrested worked in law enforcement, medical-related professions and as religious officials. 

"Other suspects were also in the process of applying for jobs working or volunteering with children," she said. 

DIA provided a range of case studies which included a North Island man sentenced to four-and-a-half years in jail on multiple charges of possessing child sexual abuse material - he was found with around 50,000 such files. DIA said there was no evidence he had escalated to physical offending, he had worked as a teacher's aide and was a local sports coach. 

Another case study highlighted a South Island man with no criminal history but an admitted 20-year habit of using child sexual abuse material, along with bestiality and torture bondage imagery. 

The man's cloud storage held more than 27,000 child sexual abuse files. When interviewed, the man revealed he regularly travelled to South East Asia where he paid families to let him abuse their children over a camera. 

"Although the offender denied engaging in sexual exploitation while abroad, it is likely from the information obtained that they were a sex tourist." 

Other case studies from around the world were provided, including one from the UK which saw two brothers arrested - one who was a night shift worker at a children's home. He was found to have downloaded abusive imagery of children while at work. His brother was also found to have hundreds of indecent images of children. 

NEED HELP? 

If you are the victim of a child abuse or sexual abuse crime call Safe to Talk: 0800 044 334 Text 4334 

If you are concerned about a child or young person who could be a victim of abuse call Police on 105 or provide information to Police via Crimestoppers on 0800 555 111. 

You can also contact Oranga Tamariki on 0508 FAMILY (0508 326 459). 

If concerned about your activity online or someone else's sexual behaviour contact: 

Safe Network: 09 377 9898 

WellStop: 04 566 4745 

STOP: 03 353 0257