Australia has three time zones:
Eastern Standard Time: GMT +10 Hours taking in Tasmania, Victoria, New South Wales and Queensland
Central Standard Time: GMT + 9 Hours 30 Mins taking in Northern Territory and South Australia.
Western Standard Time: GMT + 8 Hours taking in Western Australia
During the summer things get complicated as daylight saving time does not operate in Western Australia and Queensland, so those states are respectively one hour behind Eastern and Central summer Times.