The crucial problem for the activists is a lack of data due to the Maoists' unwillingness to allow them free access to their cantonments, children's rights activists say.

"The second phase of arms registration is the key to finding the child soldiers, and releasing and protecting them," Durga Khadka, chief of the Child Protection Unit of the National Human Rights Commission (NHRC), told IRIN.

Khadka said her organisation found a large number of child soldiers during their monitoring mission in December in nearly five Maoist cantonments. The population of child soldiers may have barely reduced, given that they are still being used in several Maoist activities, she added.