Compatibility summary
You will need a travel adapter in Papua New Guinea; plug types used there differ from Germany.
Plug comparison
Germany plug types: C F
Papua New Guinea plug types: I
There is no common plug type between Germany (C F) and Papua New Guinea (I). You need a travel adapter.
Voltage comparison
Germany: 230V, 50Hz
Papua New Guinea: 240V, 50Hz
Voltage difference is within a range many devices tolerate; check your appliance label.