Mining tycoon Gina Rinehart on Wednesday warned Australia was becoming too expensive for multinational companies who could hire workers for two dollars a day in Africa, sparking criticism from Canberra.
In a video address to the Sydney Mining Club, the world's richest woman said the nation must become more competitive as high costs force businesses offshore.
The iron ore magnate blamed the government's mining and carbon taxes, red tape and high wages for the economy's "sluggish" performance.
"Now, the evidence is unarguable -- that Australia is indeed becoming too expensive and too uncompetitive to do export-oriented business," she said.
"What was too-readily argued as the self-interested complaints of a greedy few is now becoming accepted as the truth, and more ominously is showing up in incontrovertible data."
Last week Rinehart, head of resources giant Hancock Prospecting, told Australians to "spend less time drinking or smoking and socialising, and more time working" and on Wednesday said the country should not become complacent.
"Furthermore, Africans want to work, and its workers are willing to work for less than $2 per day. Such statistics make me worry for this country's future," she added.
Her outburst came a day after iron ore giant Fortescue announced it would defer planned developments, while BHP Billiton last month shelved its multi-billion dollar expansion of the Olympic Dam copper and uranium mine.
The comments drew criticism from Prime Minister Julia Gillard.
"It's not the Australian way to toss people $2, to toss them a gold coin, and then ask them to work for a day," she said.
"We support proper Australian wages and decent working conditions."
Rinehart has been attacked by Treasurer Wayne Swan for her "self-interested" campaigns against the government's taxes on mining profits and pollution, and in the video she hit back at what she called "class warfare".
"Our federal and state governments must know that now, more than ever, we must lift our international competitiveness just to stay as well-off as we are," she said.
"And with state and federal debts, we must get realistic not just promote class warfare. Indeed, if we competed at the Olympic Games as sluggishly as we compete economically there would be an outcry."
Australian mining projects have faced headwinds from depressed conditions in Europe and the United States, softening growth in China and increased competition from other producers as well as falling commodity prices.
The price of iron ore, a crucial ingredient in steelmaking, has fallen dramatically in the past two months as the Chinese economy slows, while the price of coal, another major Australian export, has also dropped sharply.
Gillard said Australia would continue to be competitive in mining.
"We're going to compete on our great mineral deposits, our application of technology and high skills to the task. We mine differently than in other countries," she said.