US authorities have arrested 71 people in the New York City-area in a child porn sting operation, with suspects including police officers, registered nurses, a rabbi, and a Little League baseball coach.

Officials said on Wednesday that it was the largest-ever roundup of people who share child pornography online.

The suspects, which include a woman, came from "all walks of life", said James Hayes, head of the New York office of US Immigrations and Customs Encorcement.

"Other than the fact that all but one of them is a man, there is no other discernible pattern amongst them. This operation puts the lie to the classic stereotypical profile that child predators are nothing more than an unemployed drifters," he added.

"Many of the defendants are in fact well-educated and successful in the private and professional lives. They worked as registered nurses, paramedics, caretakers for mentally ill adults, computer programmers and architects."

Authorities say an alarming number of the defendants held positions of trust that gave them access to young children.

"This operation puts the lie to the classic, stereotypical profile that child predators are nothing more than unemployed drifters," said Hayes.

Among those charged was a paramedic, two nurses, an airline pilot, an au pair, two police officers and a mother accused of producing pornography involving her own child.

Those arrested face a battery of state and federal charges, including distributing, producing and possessing child pornography, Reuters news agency reported.

Authorities became aware of the file-sharing ring after the January arrest of Brian Fanelli, a former police chief in Mount Pleasant, which is just north of New York City, and the March arrest of a Brooklyn rabbi, Samuel Waldman, on child pornography charges.

'Investigation likely to expand'

Both men's computers were linked to a peer-to-peer network that allowed users to share caches of child pornography while easily importing materials from other computers linked on the network, authorities said.

During the execution of nearly 90 search warrants, agents seized 600 desktop and laptop computers, tablets, phones, thumb drives and hard drives containing tens of thousands of images and videos.

Officials said the investigation was just beginning and that it was very likely that it would expand.

"The scope of this investigation as evidenced by the number of cases spread across multiple jurisdictions is extraordinary. And the underlying conduct is appalling. No one should make a mistake here about this - that the images of child sexual assault capture actual real crimes being committed against real children, Cyrus Vance, a Manhattan district attorney, said.

Those arrested in the sting operation face between seven and 25 years in prison if convicted.