From DFAT:
This Advice was last issued on Friday, 26 September 2014. This advice contains information in the Summary and under Safety and Security (spill-over from the Syrian conflict could lead to attacks against targets in Turkey, including Ankara, Istanbul and areas close to the Syrian border. Syrian refugees have clashed with locals in a number of cities. You should exercise particular caution at times of heightened tensions). We advise Australians to reconsider the need to travel to border areas with Syria, Iraq and Iran due to the unpredictable security situation, and we continue to advise Exercise a high degree of caution elsewhere in Turkey because of the threat of terrorist attack
For More: http://smartraveller.gov.au/zw-cgi/view/Advice/Turkey