MELBOURNE TOPS LIVEABLE SURVEY FOR SIXTH TIME RUNNING

Melbourne has again topped the rankings for the world's most liveable cities while Sydney has crashed out of the top 10 because of a heightened terror threat.

Melbourne skyline (AAP) Source: AAP

THE AUSTRALIANS

* Melbourne topped the index with perfect scores for healthcare, education and infrastructure

* Adelaide was equal fifth

* Perth up one place from last year to seventh

* Sydney booted from seventh into 11th

* Brisbane ranked 16, up two places.

THE TOP 10

1. Melbourne - 97.5 out of 100

2. Vienna - 97.4

3. Vancouver - 97.3

4. Toronto - 97.2

5. Adelaide and Calgary - 96.6

7. Perth - 95.9

8. Auckland - 95.7

9. Helsinki - 95.6

10. Hamburg - 95.0.