The online chat forum, easily found via Google search, features thousands of nude photos of underage and non-consenting school students shared by boys and men who appear to know them.

The users request, swap and share nude photos of particular girls from particular high schools.

Girls from NSW schools including Wenona, Turramurra High School, Asquith Girls High, Blaxland High School, Wyong High School, Holsworthy High School and John Therry Catholic High School are among those targeted on the site.

NSW Police have joined Victoria, Queensland and the Australian Federal Police in investigating the site but they are powerless to pull it down because it is hosted overseas and uses software that allows users to post text and images anonymously.

"Detectives from the Sex Crimes Squad's Child Exploitation Internet Unit are liaising with law enforcement colleagues in other jurisdictions and making inquiries to determine if any offences have been committed in NSW," police said in a statement on Wednesday.

They encouraged anyone featured on the site to contact their local police station.

The federal police said they were liaising with domestic and international law-enforcement partners.

On the site, dozens of threads are divided by region such as Byron Bay, Wollongong, western Sydney, "North Coast Wins", "North Shore Girls" and "sluts" from the Camden area.

Regions and schools in Tasmania, Victoria and Queensland are also included.

Users request nudes of specific students or specific schools and offer to share or "dump" other nude images in exchange.

They refer to nude image uploads as "wins". Some users have hundreds of images and dump them on file-sharing site Volafile, where they disappear after two days.

"Come on boys.. post up some wins of [name redacted], you'll be the best bloke if you do," one commenter posted.

"Anybody have good wins for anyone from the north shore? Can happily contribute a lot but dont want to be the only one," posted another.

It is not clear where the photos come from, although many users appear to know the girls to whom they are referring. One user bragged about "ripping" the photos from a computer he was asked to fix.

Some users share photos from their own sexual encounters with the girls.

Other comments include:

"Any wins for Ryde chicks??"

"You got any [name redacted]? recently single and known to send nude pix. i'll dump some of [name redacted] and [name redacted] if anyone can get some."

"Any wins of [name redacted]. Massive tits, must be heaps around."

"Anyone have any Patterson River or Carrum Downs secondary sluts?"

News Corp reported that more than 2000 photos had been uploaded from at least 70 Australian schools.

Some girls who have been alerted to the site have posted messages asking for photos to be removed but are then further ridiculed or targeted by the users.

"Darling, don't be a slut and you won't end up here," one user posted to a girl who protested. "Once a photo is on snapchat or the Internet, it belongs to the Internet."

Many users on the site claim that they are all over 18, along with the women featured, but some photos depict girls as young as 14.

David Vaile, co-convenor of the Cyberspace Law and Policy community at UNSW, said it would be possible to lay charges like stalking, intimidation or publishing indecent articles.

"There is no such thing as total anonymity online. This is one of the delusions," he said. "The internet is now a vast, evidence-collecting machine but the real questions are; who gets access to it and who can be bothered doing something with it."

Despite this, Queensland Police said they do not believe it is child abuse.

"We believe the site is hosted overseas and does not appear to contain any child exploitation material," Detective Superintendent Cheryl Scanlon of the Child Safety and Sexual Crimes Group said.

"Material contained on the site are images and information that has been obtained from social media sites and from across the internet.

"We cannot stress how important it is for everyone to protect themselves online."

Direct quotes from the site have been altered slightly to prevent reverse searching.