Well Alan you've got me there. Definitely an F-28, and late 70's judging by the colour scheme. I am not recognising the background, but it is obviously a port that was served by Air Niugini F-27's as well, given the set of steps in the background on the left-hand side. It is obviously a coastal port, but does not look like any of the PNG ports I recognise. The curved-roof building is what is really throwing me. This is purely a wild guess, but could it be Honiara?
OH if correct.