Daylight Saving Time (DST) had its beginning in Australia during World War I. The Commonwealth used its wartime powers to require all Australian states and territories to put into place DST.
1917 was officially the first year DST was used across the country. It was in force between 1 January and 25 March (late summer in Australia). It was discontinued after the war, but World War II saw its return for three consecutive summers. It began with a late summer start on 1 January 1942 followed by a full summer (September - March) later that year.
Tasmania may be our smallest state, but they had great influence on why we have DST in Australia today. The Tasmanian state government implemented Daylight Savings in the summer of 1967 to save power which saved water.
By 1971 legislation was passed by all states, except the Northern Territory and Western Australia, to run a trial period. Victoria, New South Wales and South Australia made it permanent in 1972. Currently Queensland, the Northern Territory and Western Australia do not have Daylight Savings