University of Queensland researchers believe that long term population projections have a key role in informing policy in contrast with the government's population strategy released yesterday.

UQ's Queensland Centre for Population Research (QCPR) demographers have developed a new generation population forecasting model that incorporates uncertainty about the future.

Our modelling indicates there is a 95 per cent chance that by mid-century Australia's population will be between 29 and 43 million, QCPR spokesperson, Dr Tom Wilson said.

The Intergenerational Report's projection of 36 million, dubbed a "big Australia" by former Prime Minister Kevin Rudd, lies in the middle of this range.

Our model tells us there is a 50 per cent chance that the nation's population will be greater than 36 million by 2051, so we could have an even bigger' Australia, he said.

What we also know is that the majority of this growth is going to occur in mainland capital cities," the Director of QCPR, Professor Martin Bell said.

"It is surprising that the government strategy has little to say about measures that address this burgeoning growth along Australia's east coast.

Dr Wilson believes that policy targets that fall outside of the 95 per cent range of his models are beyond the realms of plausibility.

The 2326 million target advocated by the Stable Population Party is extremely unlikely, he said.

"Even a population of just 27 million has less than a 1 per cent chance of becoming a reality.

Similarly, at the other end of the scale, a mid-century population of 50 million is also very unlikely to eventuate."

He said projections of future population were essential for planning in both the public and private sectors, but conventional approaches provided little guidance on the uncertainties associated with them.

These uncertainties can include fertility rates, major recessions, government migration policy, major crises which generate refugee flows, and demand for labour in the Australian economy.

QCPR's new model is able to tackle these uncertainties by providing upper and lower limits to their projections.

Whilst it's not possible to predict population down to an exact figure, what we can do is forecast it within a certain range, with the population being very unlikely to lie outside that range, Dr Tom Wilson said.

The projections by QCPR are based on statistical models which include the variability of past demographic change and expert opinion on the future range of overseas migration.

The QCPR team's research on how these projections have been modelled is due for release in the next issue of the Geographical Research journal.

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