What this visa covers
Special Exemption is broader than “unpaid humanitarian work”
ICA says the Special Exemption Visa can be used by people undertaking paid or unpaid activities approved by the Government of Papua New Guinea. Its non-exhaustive list includes foreign officials, accredited diplomats, aid-project personnel, volunteers, missionaries, researchers, teachers, emergency-relief workers and domestic support staff for diplomats.
That means it is inaccurate to describe every Special Exemption activity as strictly non-commercial or to say every holder is prohibited from all paid activity. The restriction depends on the subclass. For example, the current Aid Worker / Volunteer eVisa class expressly prohibits paid work, while other Special Exemption categories can cover approved duties or employment-like functions authorised under that subclass.