Papua New Guinea postage stamp of 1974 with bogus overprint "O.P.M." in black, supposedly produced by the Organisasi Papua Merdeka (OPM, Free Papua Movement)
The overprint was allegedly produced for use on local courier mail in OPM-controlled areas around the Indonesia-Papua New Guinea border, but there is no evidence that such a courier service ever existed. In 1979, the Papua New Guinea Postal Administration declared these overprints to be illegal and invalid for postage.
