Economist Intelligence Unit survey editor Jon Copestake said Melbourne managed to move up one spot to claim the top ranking thanks to a slight fall in Vancouver's infrastructure score, which is one of the measures of liveability.
The Canadian city slipped to third spot, behind Vienna in Austria.
Sydney made it to sixth position in the London-based research company's latest ranking of 140 cities, from seventh in the February survey, while Perth and Adelaide again shared eighth place.
"Australia, with a low population density and relatively low crime rates, continues to supply some of the world's most liveable cities," Mr Copeland said in a statement.
"Despite the rising cost of living driven by the strong Australian dollar, these cities offer a range of factors to make them highly attractive."
Melbourne scored 97.5 per cent, just beating Vienna on 97.4 per cent and Vancouver on 97.3. A ranking of 100 per cent is considered ideal.
Brisbane came in at number 21 on the survey, two spots ahead of Wellington but behind Auckland which was number 10.
The debt crisis in euro zone countries led to a slight fall in European cities' liveability rankings.
The Greek capital Athens dropped five places due to its austerity measures and civil unrest, with its 67th place putting it below cities in emerging economies such as Montevideo in Uruguay.
Expats working in Athens could now qualify for a hardship allowance, the survey said.
The survey said the 'Arab Spring' uprisings and the Libyan civil war pushed down scores across the Middle East and North Africa with the Libyan capital Tripoli falling into the bottom 10 for the first time.
Bottom place went to Harare in Zimbabwe, which scored 38.2 per cent.
The survey ranks 140 locations as having the best or the worst living conditions, with cities scored on political and social stability, crime rates, access to quality health care, cultural events, the environment, education and the standard of infrastructure.
- AAP
