Australia brushed off on Tuesday a Chinese report accusing iron ore miner Rio Tinto Ltd of overcharging and spying on Chinese steel mills, saying it had not been officially sanctioned.

In a growing war of words with its biggest export partner, Australian Foreign Minister Stephen Smith also delivered a veiled warning to China to rein in its diplomats after China's embassy tried to block a speech in Canberra on Tuesday by an exiled leader of China's Uighur Muslim minority.

An article published online by China's state secrets agency at the weekend said Rio spied on Chinese mills for six years, resulting in the mills overpaying $102 billion for iron ore, Rio Tinto's biggest earner.

It is now quite clear, given that the article has been taken off the website, that it was essentially the opinion of the individual writer, and not if you like officially sanctioned, Smith said.

Smith said the report bore little relevance to the detention of Australian Rio Tinto executive Stern Hu and three other China-based staff of the Anglo-Australian company.

The four were detained a month ago on suspicion of stealing state secrets, but they have yet to be officially charged.

Rio Tinto's shares were some 2.2 percent lower at A$57.22 at midday on Tuesday, continuing a 3 percent slide the previous day amid investors nerves over the miner's relations with China.

Australian diplomats had made a fresh appeal for China to grant legal representation to China-born Hu after they were allowed only their second visit to his Shanghai detention center late last week, Smith said.

We were very pleased to see that his health and welfare continues to be in good order, Smith told state radio.

Chinese newspaper the 21st Century Business Herald on Tuesday quoted Jiang Ruqin, the author of the article that laid out the Rio allegations, as saying it reflected only his own views.

Jiang said his claim of losses from Rio's spying activities came from earlier media reports, but he did not reveal where he had got information that Rio had been spying for six years.

The website ( was inaccessible on Tuesday, but the article could be found on other Chinese-language websites.

David Kelly, a professor of Chinese studies at the University of Technology, Sydney, speaking in Beijing, said it was unclear how much Chinese government weight was reflected in the article.

I would suggest that at least it reflected a powerful view of at least part of the bureaucracy, said Kelly.

In a further sign of brittle relations, the Chinese embassy's political counselor, Liu Jing, asked management at Canberra's National Press Club last week to drop an invitation to Rebiya Kadeer to speak on Tuesday, the club said.

Kadeer is blamed by Beijing for instigating last month's ethnic riots in Xinjiang province, which left 197 people dead, mostly Han Chinese, and wounded more than 1,600.

Embassies, diplomats, officials are entitled to put views in Australian society, but when they put those views, those views have to be put appropriately, Smith said.

The Australian newspaper said in an editorial on Tuesday that Australia's Mandarin-speaking prime minister, Kevin Rudd, was increasingly irritating Chinese leaders with his conviction that he had a special relationship with Beijing and could therefore be outspoken on Chinese internal affairs.

(Additional reporting by Chris Buckley in BEIJING and James Grubel in CANBERRA; Editing by Jeremy Laurence)