Police last week carried out a major sweep-up operation on people suspected of possessing and distributing child pornography.
In total 140 households were raided in connection with the crack-down, involving 11 police teams nationwide.
A total of 1,750 computers, usb sticks and telephones were seized containing tens of millions of images and thousands of films, Nos television said. Their contents are now being analysed and arrests will follow.
The raids were based on reports of people downloading child porn via hotlines in the Netherlands and the US as well as via social media, Google and Microsoft, Nos said.
Further sweeps are being planned, the department is quoted as saying.