Australia's population races to 27 million

With an an annual increase of 659,800 people Australia's population reached 26.8 million at September 30.

ABS head of demography Beidar Cho said while all states and territories registered an increased population, Western Australia had the largest growth.

"Western Australia had the fastest growing population, up 3.3 per cent compared with the previous year," she said.

"This was followed by Victoria, which grew by 2.9 per cent, and Queensland which grew by 2.7 per cent."

Research found the population growth was largely fueled by overseas arrivals, with overseas migration accounting for 83%, while the remainder was considered a "natural increase."

"Net overseas migration grew by 60% compared with the previous year, driven by an increase in overseas migration arrivals (up 34%), predominantly on a temporary visa for work or study," Ms Cho said.

Net overseas migration to Australia was 548,800 people with 765,900 overseas migration arrivals and 217,100 departures.

The population unofficially reached 27 million on January 24 with the ABS population clock ticking past the big number.