Apple has made a big announcement on safety concerns with AC Adapters that came with most apple products released from 2003-2015.
Your apple ac adapter might look like a complete adapter by itself, but it has detachable parts as shown in the picture below.
Apple released a statement on 28 Jan 2016 showing the detachable flat angled prongs as eligible for replacements in their exchange program as shown below:
The back slot would have numbers or no numbers. Once you've identified the detachable two prong plug adapters, all that is needed is to get it exchanged. Simply by going to the Authorised Service Provider (One company registered for Cairns came up as Talk To The Mac with one at Grafton St in the city and Smithfield Shopping Centre) or have the replacements mailed to you. Dig up all the serial IDs for all your affected Apple AC Adapters, sign in to your apple ID, come to the end page that is clearly not up to speed with the Exchange Program, (giving instructions to send your perfectly fine Apple product to them as is with the case of a normal send by mail repair job), ignore the end page, receive an email few days later confirming the replacement part will be delivered. Meanwhile, if it looks unsafe; it probably isn't. Stop using it and stay safe.