Kibulu Dubu and others, I do not agree with you saying applicants should send the originals. That's crazy suicide in a country like PNG where there is no efficiency in mail delivery and transparency in procession. Where is the gurantee that you'd have your original certificate being returned safely if you are applying from Manus for a job in POM for instance? How would you know that the address that you are using is reliable and and genuine?
The best way, like done almost everywhere in the world is to take a copy of the original plus the original itself to the Court House. There, officials with stamp and sign the copy after sighting the original. They can do that to as many copies as possible so that you can send the certified copies and still keep your original. You can then present the original at the interview for sighting which is the best way that I know of and it's working well in other countries. Only few institutions in PNG do that.