A Queensland man has been arrested and other arrests in Australia are expected after authorities in the Philippines rescued three sisters aged eight, nine and 12 and an 11-year-old girl, based on information partly provided by the AFP.

The mother of the sisters and two other women have been arrested and charged with human trafficking, child abuse and forcing the girls to engage in explicit sex acts.

The children are being cared for in a shelter for abused children in Bacolod City, 720 kilometres south of Manila, where the offences allegedly took place.

"The children were innocent," said Arlyn Torrendon, a policewoman who was part of a team that rescued them.

The arrests come two weeks after Philippine authorities, acting on an overseas tip-off, made one of the largest seizures of its kind in the country, uncovering a major operation live-streaming the abuse and torture of children from dark corners of the internet to predators in Australia, the US, Canada and Europe.

Authorities seized a mobile HD tablet contacting more than 4000 contacts, numerous computers and 30 hard drives.

Police said they caught 53-year-old American David Timothy Deakin in his two-storey apartment that had been converted into a cybersex den in Mabalacat, 84 kilometres north-west of Manila, while he was allegedly streaming illicit content through a "dark web" site that disguised his identity. The apartment is in a red light district near the Clark air base, which was operated by the US Air Force until 1991.

Police burst into the filthy apartment and grabbed Mr Deakin as he was allegedly about to wipe video and images of children engaged in explicit sex acts from his computers.

Inside the den police found children's underwear, toddlers' shoes, cameras, bondage cuffs, fetish ropes and stacks of hard drives and photo albums.

On a wall someone had scrawled "my Mum and Dad love me" and a broken heart.

Authorities expect the seizure will lead to multiple arrests and the rescue of child victims.

Mr Deakin, a computer expert who had been living in the Philippines since 2001, has been charged with cybercrime, child pornography, child abuse and child trafficking, and could face life in jail if convicted.

Soon after his arrest he claimed he was just a cybersex customer but then changed his story to say shocking images might have inadvertently slipped into his computer when he downloaded massive files using BitTorrent, a data tool that can move and sort a large amount of digital content.

"I'm a schizophrenic," he told the Associated Press.

The AFP also played a key role in the arrest in the Philippines of 52-year-old alleged Australian child sex predator and "dark web" mastermind Peter Scully, who has been charged over what police say are the most shocking cases of child murder, torture and abuse they have seen in the country.

Scully, a former Melbourne businessman wanted on fraud charges, is accused of directing and participating in scores of depraved videos, including one where horrific injuries were inflicted on an 18-month-old girl.

Scully has pleaded not guilty to 75 charges at his ongoing trial in a southern Philippines court, forcing his victims to undergo the ordeal of testifying against him.

The Philippines has emerged as the centre of a booming cybersex industry using new digital technologies that the FBI describes as an "epidemic", with 750,000 child predators online.

Widespread poverty that means operators can easily find vulnerable children, increased internet speeds and international cash transfer systems have attracted a growing number of cybersex criminals to the country.

Pocket wi-fi, mobile phone internet and other technologies have allowed them to be highly mobile, police say.

Predators usually use bitcoin or untraceable credit cards to send payment to criminals who set up child sex acts and abuse in front of webcams, they say. The more abusive the show, the more the customer pays.

The children usually receive between $10 and $100 for participating in each "show", while predators overseas pay thousands of dollars to watch.

Police said the mother of the three sisters arrested in Bacolod City was an impoverished widow.

An AFP spokesman declined to comment because of ongoing operations and referred Fairfax Media to Philippine authorities.

with AP