Migration main factor as Melbourne grows fastest

Australia's population is booming, driven largely by an increased birthrate and an increase in overseas migration. But analysts warn the country must make sure it has the infrastructure to match the population surge.

An aerial view of central Melbourne Source: AAP

The major cities along Australia's east coast -- Sydney, Melbourne and Brisbane -- now account for more than 70 per cent of the country's population growth.

The latest figures from the Australian Bureau of Statistics show Sydney remains the country's largest city with a record 5.1 million residents last year, up by 2 per cent.

But Melbourne, at 4.9 million, is the fastest-growing city in the country after an increase of 2.7 per cent in the past 12 months.

And Brisbane, the other fastest-growing, is also at 2 per cent in the last year.

The Bureau of Statistics' director of health statistics, Louise Gates, points to migration as the biggest factor for the fastest-growing ones.

But the Gratton Institute's Brendan Coates says a larger population is not always better.