China has accused Rio Tinto of spying on its steel industry for six years, costing the country Rmb700bn ($102bn) in excessive charges for iron ore and highlighting the need for Beijing to overhaul the way it deals with state secrets so that it can better fend off any systemic threat to its economic security.

The remarks, contained in an editorial in the magazine of the National Administration for the Protection of State Secrets, indicate that Beijing's detention of four Rio employees in China on accusations of stealing state secrets about iron ore price negotiations could be the start of a widening campaign rather than an isolated case.

“From the large amounts of intelligence data that was found on Rio Tinto computers . . . it is clear that the economic spies, using bribes for six years, forced the Chinese steel companies . . . to pay more than Rmb700bn more for imported iron ore than they would otherwise,” the NAPSS said.