It may depend on what the documents are being used for. If it's for transactions back "home" it may need a particular type of "certification." You may want to check with the Australian consulate to see what they recommend if that is the case.
Thank you Crabtree, DejW and Bev for your suggestions. I am aware of various ways to achieve the certification - and many are acceptable. My post was made because if there were a Justice of the Peace (Australian) operating somewhere in this area it would make a number of specific certifications far simpler. If there isn't one that is fine, worth a try - just trying to take the less complicated path over the more complicated one.
Living at Sainte Foy le Grande and was a JP until about 6 months ago when I resigned the position due to inability to keep up to date on issues back home. Sorry that I cannot help. Not sure that OZ will accept JP's being out of the jurisdiction for more than 12 months.