The world's most wealthy woman is warning that firms are in danger of having to abandon iron-ore mining in Australia if wages are not cut, pointing out that African miners are "willing to work for less than $2 per day."

In a video recently posted on the Sydney Mining Club website, 58-year-old Gina Rinehart -- who has amassed a $18 billion fortune through iron-ore prospecting -- said that Australia could be more competitive by emulating Africa.

"We must be realistic, not just promote class warfare," the billionaire explained. "Indeed, if we competed at the Olympic games as sluggishly as we compete economically, there would be an outcry."

"The evidence is unarguable that Australia is indeed becoming too expensive and too uncompetitive to do export- orientated business," she insisted, adding that "Africans want to work. Its workers are willing to work for less than $2 per day."

Under current exchange rates, $2 a day in Australia is worth about $2.04 in U.S. dollars.

"It's not the Australian way to toss people $2, to toss them a $2 gold coin and then ask them to work for a day," Australian Prime Minister Julia Gillard told reporters on Wednesday. "We support proper Australian wages and decent working conditions for Australian people."

Rinehart came under fire last week after she wrote a column urging those "jealous" of the wealthy to "spend less time drinking or smoking and socializing, and more time working."