Rio Tinto Ltd said on Wednesday that the company is re-assessing its existing Australian projects for a worst-case tax scenario possibility as it studies the effect of the proposed resources super profits tax on future growth projections.

Company chair Jan du Plessis informed shareholders through a letter that so far, almost half of Rio Tinto's assets are located in Australia, which should explain recent sentiments aired by chief executive Tom Albanese, describing the country as his number one sovereign risk concern.

Mr du Plessis affirmed that indeed other countries would benefit should mining industry players shift their focus from Australia to other tax attractive locations such as Chile, which along with Canada, declared on Tuesday that the super profits tax would be an opportunity for them to secure a better share of the global minerals market.

He reiterated that Rio Tinto is gravely concerned on the fundamentals of the new tax, which "has been developed in a vacuum and is divorced from the day-to-day realities of business," as he added that the company is specifically wary of the tax's applications to the resources industry's ongoing projects.

On the other hand, Mr du Plessis said that Rio Tinto is always open to cooperate with the Rudd government on tax measures that "would not damage Australia's competitiveness, its mining industry or the superannuation funds of millions of Australians."

Meanwhile, Prime Minister Kevin Rudd belied on Tuesday claims made by Rio Tinto that his government had refused to engage in any dialogue with the company in order to discuss the planned tax on the mining industry.