Record births, but wave of migrants push nation past 23million

Australia's population will tick past the 23 million mark on Tuesday night, as the country continues to grow at the fastest rate in the developed world.

The Australian Bureau of Statistics' population counter will tick over to 23 million at 9.57pm. Social researchers say the milestone baby will most likely be a boy called Jack. Odds suggest his mother will be 31, his father 33 and he will live in western Sydney.

Jack is not real, of course. His likely arrival time has been reached by averaging the expected number of births, deaths and net overseas migration intake (incoming residents minus outgoing) since data was collected in September last year.

What is known is our annual population growth rate of 1.7 per cent - 1048 people per day - is the fastest of any Organisation for Economic Co-operation and Development country. The US is growing at 0.9 per cent and Britain at 0.6 per cent.

The world's population is growing at 1.1 per cent, having surpassed 7 billion people in late 2011. Australia's population growth rate is even outstripping countries with traditionally high birth rates, such as India on 1.4 per cent.

Demographers say it is migration, rather than an elevated birth rate, that is the main driver spurring Australia's growth.

Net overseas migration accounted for 60 per cent of Australia's population increase last year, with the proportion from births falling from 46 per cent to 40 per cent.

Bob Birrell, of Monash University's Centre for Population and Urban Research, said aside from a surge in the early 2000s, Australia's fertility rate (the number of children per woman) has remained stable at about 1.9.

He said the population was largely driven up by people on temporary visas, who make up about half the growth in net migration.

''Working holidaymakers, visitors, 457 visa holders, New Zealanders - they have all been going up sharply, '' he said. ''There is no cap on working holidaymakers and we are a very attractive destination now for people from Ireland, Taiwan, England, where the labour markets are dead.''

Almost two-thirds of permanent arrivals last year were on some kind of working visa - 30 per cent were on family visas and 7 per cent on humanitarian visas.

Bjorn Jarvis, director of demography at the ABS, said the 488, 100 permanent arrivals last year was proportionally a smaller group relative to the rest of the population than the influx after World War II.

Births still hit a record high last year, surpassing 300, 000 for the first time. Australia recorded twice as many births (303, 600) as deaths (149, 100). By 2028, there will be more people aged over 60 than under 20.