Police have arrested a 24 year old man in Denmark over the persistent online attack on an Auckland school girl.

The Danish citizen has been charged with cybercrimes relating to the online posting of private photos and hacking of private computers under Danish law.

It comes following a joint investigation by New Zealand Police, the Danish National Cyber Crime Centre and South-East Jutland Police called Operation Cavern.

The man will be brought before the Court of Kolding Town in a closed hearing where police will ask for him to be remanded in custody.

South-East Jutland Police prosecutor, Neils Tipsmark, said the cooperation with New Zealand has been smooth and fruitful.