Papua New Guinean teenagers are travelling unaccompanied to neighbouring Indonesia's Papua region to study Islam.
The trend has come to the attention of PNG's Consul General in Jayapura, the capital of Indonesia's Papua province.
Geoffrey Wiri said in recent months there had been an increase in young PNG people coming across.
"There's about six of them there right now in Jayapura," he said.
"I raised concern with our authorities back here in PNG that, look, these children are going over there unattended, unaccompanied, and they're going on their own will to learn something that they've got no idea what they're learning about."
Mr Wiri said the six teenagers, who come mostly from PNG's Highlands region, were being looked after by a Muslim organisation in Jayapura.
But he expressed concern that the teenagers had their unsigned passports processed when travelling to Indonesia.
Mr Wiri said the children - youngest of whom is aged 12 and the oldest is 15 - now go by Muslim names.
"We can't track back to their families back home because they're using Muslim names," he said.
Of the place where they had come to study, "it's kind of a restricted school where only these people go and there's one teacher," he explained.
"My concern is, what's the benefit, when they go back (to PNG) what's the result?"
The Consul General said the six teenagers were not the first group to come across to Indonesia's Papua.
"There have been other people from PNG that have come through the Muslim training in Jayapura," he said.