The Australian government is prepared for a long haul in dealing with China's detention of a senior Australian mining executive on suspicion of stealing state secrets, Foreign Minister Stephen Smith said on Sunday.

Smith, speaking to reporters in Perth, added that Chinese authorities had still not revealed to Australia any evidence in support of their decision a week ago to detain four Rio Tinto employees, including its top iron ore salesman in China, Australian Stern Hu, on suspicion of espionage.

The affair has cast a shadow over Australia-China relations.

(Reporting by Fayen Wong, writing by Mark Bendeich; Editing by Darren Schuettler)