SYDNEY - Australia's population grew at its fastest rate in 50 years in the 12 months to March thanks to a surge in migrant numbers, official figures showed Tuesday.
The population grew by almost half a million people, or just over two percent, to 21.8 million, with almost 300,000 immigrants, the Australian Bureau of Statistics (ABS) said.
"The last time Australia saw higher growth rates was in the 1950s and 1960s as a result of post-war migration and high birth rates," the ABS said.
The growth rate had almost doubled in five years, it added.
Treasurer Wayne Swan last week released population projections showing the number of Australians would grow by almost two-thirds to 35 million by 2049, posing an economic threat as serious as climate change.
Conservationists said the figures showed Australia's population was "on a collision course with our natural environment" and called for migration to be cut to more sustainable levels.
"Each additional one million people adds 25 million tonnes of pollution to Australia's greenhouse accounts," said Charles Berger from the Australian Conservation Foundation.
"We need a long-term population policy aimed at stabilising our population and consumption at sustainable levels and helping other countries to do the same."
But Immigration Minister Chris Evans said temporary skilled migrant numbers were already in decline, following cuts to the program in response to the global economic downturn.
"The Australian labour force will start to decline over the coming decade without adequate levels of skilled migration," Evans said.
"A healthy level of skilled migration will offset the impact of our ageing workforce to maximise our productivity levels and to support our ageing population," he added.
According to projections, the senior population is set to double and the number of elderly people will expand four-and-a-half-fold.
The ratio of retirees to working-age Australians is expected to drop to 1:2.7, from 1:5 currently.