The following links may be of interest to you.
Papua New Guinea
The Australian National University’s Pacific Institute has a digitised archive of Pacific research. The archive is available online. There are many papers on PNG. In particular, there are a series of books on old PNG elections. These are an amazing resource if you want information on the country’s electoral politics. You can access the Pacific Institute’s digital archive here. You can find election material by scrolling down to the heading ‘PNG Elections’.
Edward Wolfers, Emeritus Professor of Politics at the University of Wollongong, has created an index of local and electorate-level studies that can be found in the election books. This is an invaluable tool if you want to find out which electorates and areas were covered in individual books. You can download it here.
Elections elsewhere in the Pacific
An archive of Solomon Islands election results, as well as useful accompanying information, can be found here.
Pacific Islands Statistics
Although the data are incomplete, the SPC’s PRISM and PopGIS tools provide information on other attributes of Pacific Island countries. Pacific Web also has excellent data from old censuses and other studies.