Brisbane's population will grow at nearly twice the rate of Sydney's, more than doubling in the next 40 years, federal Treasury has projected.

Speaking at the Queensland University of Technology yesterday, Treasury secretary Ken Henry said Brisbane's population would hit 4 million by the year 2049.



Dr Henry voiced fears that Australia might be unable to handle another 13 million people by 2049 without serious environmental losses.



''With a population of 22 million, we haven't managed to find accommodation with the environment,'' he said.

''Our record has been poor, and in my view, we are not well placed to deal effectively with the environmental challenges posed by a population of 35 million.''