On the "Postage Paid" webpages you will find the following types of markings:
"Postage Paid" and "Newspaper Postage Paid" markings have been used in Papua & New Guinea since 1950. A variety of other "Postage Paid" types were added thereafter. Yet to be verified are the earliest dates for "Postage Paid" markings on official mail.
As with a lot of other collecting periods, the "Postage Paid" markings are a sad situation on the outer edge of our interests. On the contrary, these markings belong in every country collection. They originate out of the postal need and are uncommon, even scarce, when one wishes to have nice clean strikes. For our illustration, many of the markings had to be enhanced. To search for covers, showing that kind of clear marking, may well be in vain.