AUSTRALIA desperately needs an integrated population policy if the country is to survive predicted population increases, politicians and environmentalists say.

Queensland's population topped 4 million last month, increasing by a record 112,666 people or 2.6 per cent in the year to March 31.

Queensland Treasurer Andrew Fraser said the state's population was expected to reach 5 million in 2016, 6 million in 2028, 7 million in 2042 and 8 million in 2057.

Federal Treasury Secretary, Ken Henry said Brisbane would double its population to 4 million by 2049 and Australia's population would climb to 35 million in the next 40 years. Mr Henry said we had a ''poor'' record when it came to the environment and questioned how we would deal the challenges of such population increases.

Former sustainability minister Andrew McNamara believes there are already ''too many of us'' because Australia has no population policy. ''Traffic is congested, trains overcrowded, we have long waiting lists in hospitals, can't afford housing, urban sprawl is causing social alienation and environmental problems are overwhelming,'' he said.