US miner Cliffs Natural Resources has escalated its critique of Australian iron ore miners, accusing them of supplying China with the materials to launch its territorial advances into the South China Sea.

In another emotive attack on iron ore exporters such as Rio Tinto and BHP Billiton, Cliffs chairman and chief executive, Lourenco Goncalves, said the miners were supplying China "to become an enemy".

US miner Cliffs has linked Australian iron ore exports to China's moves on the Spratly Islands in the South China Sea.

"I hope the Australians will continue to question themselves why one or two companies are giving their finite resource away to the Chinese while the Chinese builds into a military powerhouse in the South China Sea," he said in a conference call with analysts on Friday.

"I believe that China is a disaster. I believe that China will bring Australia down.