Indonesian authorities are investigating whether a child pornography ring had links to an international network, police said on Tuesday, after videos of adult women engaged in sexual acts with boys went viral on social media.

Police in West Java province said three boys as young as seven and who figured in the videos are now in the care of social workers.

At least five people have been arrested, including the mothers of two of the boys, on suspicion of violating child protection and pornography laws. They could face up to 15 years in prison.

"Results of the preliminary investigation show that the director sold the videos to someone in Russia and Canada," said regional police spokesperson Yusri Yunus.

Yunus said the motive of those involved was to make money.

"We are still investigating and co-ordinating with the national cybercrime unit."

The director received $2,700 Cdn to make the videos, media have said.

Indonesia has been vulnerable to child pornography and sexual abuse of minors because of poverty and lax enforcement of laws in the past.

Authorities stopped 92 convicted Australian pedophiles from entering the country last year, based on immigration data.

In a case that shocked Southeast Asia, a British court handed Richard Huckle 22 life sentences in 2016 for abusing up to 200 babies and children, mostly in Malaysia, and sharing images of his crimes on the dark web.

UNICEF says the Philippines is the top global source of child pornography.