A quick glance at the Bureau of Statistics population clock tells us we'll reach a high point of 23 million as early as next week, well ahead of any previous prediction. This will bring population into sharp focus before the 2013 federal election.

Australia's population is growing by more than 1 million people every three years. That's the size of Adelaide.

Our growth rate now stands at an extraordinary 1.7 per cent a year. By comparison, the world average is 1.1 per cent, with most developed nations well below this average.

In June 2010, Julia Gillard promised she would not pursue Kevin Rudd's ''big Australia'' population target of 36 million by 2050. Why? Rudd's unpopular stand became a flashpoint on talkback radio and reflected poorly for Labor in the polls. Gillard sensed this and used her first major announcement as Prime Minister to reassure disenchanted voters she did not believe in a big Australia. She unequivocally stated ''Australia should not hurtle down the track towards a big population.''

But what has happened since?

Baby bonuses remain on offer and the permanent immigration program has been increased - yes, increased. We are now on target for not 36 million but 40 million by 2050. Under Gillard, the permanent immigration program stands at more than 200,000 a year - the highest level in Australian history. On top of this we have more than 50,000 New Zealanders now freely crossing the ditch annually, without proper immigration management such as skills testing. To add to the population explosion, a recent Gillard government decision grants foreign students automatic working rights for up to four years, irrespective of their field.

In short, Gillard has spectacularly broken her first promise as PM. She even recently admitted that Australia would continue to run ''a sizeable immigration program''.

Regardless of whether you support a big Australia or a stable Australia, the 23 million mark gives us all a chance to reflect on whether population growth remains in our best interests. Has ''populate or perish'' become ''populate and perish''? To help our analysis, we can refer to a number of studies. These include the seminal Australian Academy of Science study in 1994.

In considering the resource needs of cities, and supply of water, minerals and arable land, it concludes: '' … the quality of all aspects of our children's lives will be maximised if the population of Australia by the mid-21st century is kept to the low, stable end of the achievable range, i.e. to approximately 23 million.''

As Australians see their environment and quality of life deteriorating due to population growth, this conclusion appears sound. This optimum level was determined before issues such as climate change and peak oil came to prominence. What would their conclusion be today?

For too long, the population debate in Australia has been dominated by the extremes: business lobbies seeking more customers and anti-immigration groups promoting intolerance. As we approach 23 million, Australians of all backgrounds crave a rational and mature debate on population sustainability, free of simplistic and divisive distractions.

We live in a finite world, so can't grow forever. At some point, Australia must grasp the nettle and upgrade from immigration nation to mature, stable and sustainable nation. A stable population is necessary, and the sooner we act, the easier it will be to manage the growing environmental problems.

Population choice is critical in determining the sustainability of the environment, economy and quality of life we enjoy and pass on to our children. That's something we all deserve a say on, not just vested interests with government access.

William Bourke is president of the federally registered Stable Population Party.