Sydney's eastern suburbs have the highest rate of colonoscopies in the nation,  according to Australia's first ever report on the way healthcare varies nationally.
Children living in Mosman are six times more likely to have their tonsils removed than those living in Marrickville, and women from Lake Macquarie are five times more likely to have hysterectomies than those from La Perouse.
If you are a diabetic in Wollongong, your chances of having a limb amputated are higher than if you live in Wahroonga, and the Southern Highlands has the highest rate of antipsychotic prescriptions in Australia. 
The Australian Atlas of Healthcare Variation found stark differences in the rates of medical and surgical interventions, which were largely "likely to be unwarranted", according to where people live.
It was released on Thursday by the Australian Commission on Safety and Quality in Health Care.
Professor Villis Marshall, chairman of the commission's board said: "Australia has a world-class health system but it is crucial we study what these variations might tell us about how to do things better and more consistently in the future".
The rate of colonoscopies performed in Sydney's eastern suburbs was 30 times higher than the area with the lowest rate and double the national average.
The procedure is controversial as it is believed to be overused.
Some of the areas with the highest rates of antibiotic prescribing in Australia are in western Sydney, including St Marys, Fairfield, Green Valley, Mt Druitt, Liverpool and Bankstown.
Women in regional areas were more than five times more likely to undergo a hysterectomy than women in metropolitan cities, ranging from 225 per 100,000 women in the Northern Territory to 349 per 100,000 in Western Australia.
Hysterectomies were often performed to treat heavy menstrual bleeding, and less commonly to treat chronic pelvic pain and endometrial cancer.
The report said doctors and patients in different areas could have used different criteria to decide when to recommend and agree to treatment, and specialists may be more available in metropolitan areas.
"Even when the highest and lowest rates were excluded, the rate was almost three times higher in one local area compared to another," said the report, which examined data from the Medicare Benefits Schedule, the Pharmaceutical Benefits Scheme (PBS) and national patient admissions data.
The prescription of medicines for attention deficit hyperactivity disorder (ADHD) , anti-depressant medicines and anti-psychotic medicines to children younger than 17 also varied greatly by location. NSW and Queensland had the highest rates of dispensing these medicines. 
Older people were also far more likely to be prescribed with anti-depressants, with 400,000 of 15 million prescriptions given to children and young adults in 2013/14, compared with more than 6.5 million for people aged 65 and older.
The report did not conclude "ideal" national levels of various treatments, but found a number of reasons for the differences, including that clinical standards were not strictly adhered to, and both patients and doctors lacked clear guidelines on when treatments were needed.
"The challenge in identifying and addressing unwarranted variation is that for many healthcare interventions we do not know what rates of intervention deliver the best outcomes for patients and the broader community," the report said.
Health literacy rates also needed to be improved - it estimated about 60 per cent of Australians had low health literacy - to help patients understand the decisions they make about their health.
This was particularly needed in disadvantaged areas where low understanding, coupled with lower access to healthcare services made it harder to compare the risks with the benefits of surgery and understand different treatment options.
More consistent guidelines needed to be adopted in some areas, and state and territory health departments needed to better review the stark differences and come up with plans to address them.