"These cases are tragic," Licadho director Naly Pilorge said in a statement.

"The birth families were cheated, adoptive parents were tricked and the children have been robbed of their true identities," she added.

"They all deserve to know the truth of what happened, and those responsible for these hideous crimes should be held to account," she said.

The report also called on Cambodia's government and the governments of the receiving countries to apologise to those affected by the scheme.

Cambodia has been grappling with the murky world of orphanage businesses for years now, with many operating under the radar and ignoring government orders.