DAYLIGHT saving will begin tomorrow in NSW, Victoria, Tasmania, the ACT and South Australia.
Clocks will go forward one hour at 2am tomorrow, October 3, and wind back on Sunday, April 3, next year.
Queensland, Western Australia and the Northern Territory do not have daylight saving.
This weekend's time-shift will again plunge millions of Australians into temporary sleep debt, which experts warn can trigger a jump in workplace accidents and heart attacks.
While it delivers an extra hour of daylight during waking hours and reduces energy use, Associate Professor Greg Murray said the change also posed some short-term risks and challenges.
"Initially there is an acute sleep deprivation of one hour," Dr Murray, from Melbourne's Swinburne University of Technology, said on Friday.
"On top of the chronic sleep deprivation that many people suffer, this additional loss of sleep appears to cause decreased alertness, concentration and mental performance."
An analysis of workplace accidents shows almost a six per cent increase in the week following the time-switch, attributed to reduced alertness caused by loss of sleep.
Heart attacks increase by five per cent, Dr Murray said.
There was evidence of a rise in alertness-related car crashes though the picture was complicated by improved lighting during the evening traffic peak.
However, he said once the body had adjusted, there were clear benefits.
"We have more daylight time in which to exercise, socialise and get some sunlight exposure, which are good for mental health and wellbeing," Dr Murray said.
With the resumption of daylight saving, Sydney, Melbourne, Canberra and Hobart will be:
- 2 hours behind New Zealand
- 1.5 hours ahead of Darwin
- 1 hour ahead of Brisbane
- half an hour ahead of Adelaide
- 1 hour ahead of Port Moresby
- 3 hours ahead of Perth
- 4 hours ahead of Jakarta
- 10 hours ahead of London, until Oct 31 when it becomes 11
- 18 hours ahead of Los Angeles, until Nov 7 when it becomes 19
- 5 and a half hours ahead of Delhi
