Hi Panda,
i graduated in 2003. Then graduated UTS in 2009 doing electrical engineering. I landed a job at John Holland as a graduate engineer in 2010. The work predominantly given to graduates is in the line of project management and site establishment, procurement, quality, safety, communication, stake holder and interface management.
My recommendation is choose Civil Engineering because there are numerous projects in Australia. Regardless of the type of engineering, the foundation is the same. Engineering teaches you to handle real life work challenges with limited resources and time.
If you want to do petroleum engineering, i recommend to do "mining engineering at UNSW" instead. I had a friend drop out of electrical and did mining engineering. The work is very hard. The hours are long and generally it is fly in fly out with a schedule of 14 days on 5 days off. The pay is fantastic - starts at around 140k for a graduate.
hope this helps
Van