Two Dutch nationals have been arrested in connection with a major investigation into child pornography and child abuse abroad, the public prosecution department has confirmed.

Henk K, who is 75, was arrested in Nepal on Friday and an unnamed 46-year old man was picked up at his home in Zuid-Holland.

In total, four homes in the Netherlands were raided in connection with the investigation and further arrests have not been ruled out, the department said in a statement.

Child rights organisation Terres des Hommes is keeping watch on at least 350 Dutch nationals who go on holiday to have sex with children, the Telegraaf said on Monday. Their number include the two men picked up last week, the paper said.

Spokesman Gideon van Aartsen told the Telegraaf that the 350 people came into the spotlight as part of a special cyberspace project and that their online activity is now being monitored.

‘Child sex tourists have all sorts of friendships in countries where sex tourism is a problem,’ Van Aartsen told the paper. The organisation also says it works with airlines to monitor sex tourists’ travel arrangements.

According to the Telegraaf, most of the 128 Facebook friends belonging to Henk K, arrested in Nepal at the weekend, are Nepalese teenagers. K, who is 75, has a house in Nepal and has been visiting the country for years.