Indonesia has apologised for some of its troops crossing the Papua New Guinea border.
Papua New Guinea's newspaper, the National, quotes an Indonesian embassy official as saying new soldiers had not been briefed about the location of the border markers.
He says they were deployed in May and did not receive technical briefing of the boundary.
He went on to say most of them are young and must have been carried away by the beautiful scenery and did not realise what they had done.
The official, however, denied reports of five incursions by Indonesian soldiers between late May and last week.
Meanwhile, the PNG Defence Force commander Commodore Peter Ilau says he has received a letter from the Indonesian military expressing regrets about these incidents.