By Agence France-Presse
Evrard Nicolas Sarot, 53, was a detained on Tuesday in Siem Reap province with pictures on his iPad and a digital camera of naked boys aged between 11 and 15, according to police.
"At this early stage, there are 20 boys but the victims could be more than this. This is a big case," Duong Thavry, chief of provincial anti-human trafficking police said, adding officers found thousands of photos of naked boys in his possession.
The Dutchman, who has frequently travelled to Cambodia as a tourist since 2011, will appear before court on Thursday.
If found guilty "he faces between seven and 15 years in prison for producing child pornography," she added.
The suspect convinced the boys to follow him to a quiet place and then asked them to perform erotic poses for between $1 and $4, according to Action Pour Les Enfants (APLE), an NGO that hunts paedophiles.
Cambodia is battling a reputation as a haven for foreign peadophiles, who take advantage of widespread poverty and poor -- and often corrupt -- law enforcement to abuse children.
Sarot's arrest marks the third foreigner held over child abuse allegations in Cambodia this year, APLE said in a statement.
Last week, a 47-year-old Cambodian-American was also arrested by Cambodian police for allegedly sexually abusing 11 underaged boys.
In February, a Dutch paedophile was jailed in Cambodia for five years for sexually abusing children over a decade, after several police probes failed to stop his predatory crimes.
The country launched a drive to shed its reputation as a child sex hub in 2003 and has since prosecuted dozens of foreigners for sex crimes, but significant lapses in policing remain.