The Kazakh government is planning a power grab for Kazakhmys and ENRC, raising corporate governance concerns over its influence on the FTSE 100 mining companies.
Fears are escalating in the City that the state's move to increase its holding in Kazakhmys and, potentially, ENRC may be a worry to insitutional investors, who buy blue-chip shares for UK pension funds.
The Kazakh sovereign wealth fund yesterday raised its stake in Kazakhmys to 26pc, netting the miner's chairman, Vladimir Kim, £850m for an 11pc stake.
The government will be Kazakhmys's largest shareholder if Mr Kim goes through with a plan to list a further 4pc of the £7.64bn copper miner in Hong Kong.
Yesterday, Zhandos Abishev, director of mining at the sovereign wealth fund, Samruk-Kazyna, said the state also wants to increase its stake in ENRC within six weeks.
"We will probably try to raise the quantity of shares in ENRC as we have in Kazakhmys, perhaps to 25pc," he told The Daily Telegraph. "The investment of the government will strengthen the company and show it is going to to implement more projects in Kazakhstan."
Samruk-Kazyna, which counts former BAE chief Dick Evans as a board member, has been consolidating its power across Kazakh industry in recent months.
Earlier this year, the government passed Kazakhmys $2.7bn of a $10bn loan provided by China during the financial crisis.
Analysts have previously queried the large amount of spending on "social projects" required of the companies by the Kazakhstan government.
Industry is bankrolling the huge National Library of Kazakhstan, with Kazakhmys giving around $100m a year to various projects.
Louise Collinge, an analyst at Evolution, downgraded the company to a "reduce" rating. "We are cautious about the implications of these moves," she said. "There may well be a call for more social funding."
A recent Global Witness report, strongly denied by Kazakhmys, described the miner as being run primarily for the benefit of a handful of people connected to the Kazakh government. "What do investors know about the politics of Kazakhstan? Really very little," said Tom Mayne of Global Witness.
British pension funds are the largest investors in FTSE 100 companies – and many so-called "tracker funds" must invest in blue-chip companies regardless of any doubts about an individual business.
Other analysts point out that Kazakhstan's grip over Kazakhmys may increase following the death last month of its country chairman, Vladimir Ni, a close friend of the president. Kazakhmys denied the events were related and insisted the sale was because Mr Kim wanted to "diversify his investments".
Kazakhmys numbers Lord Renwick, an ex director of British Airways and BHP Billiton, among its board members.
ENRC declined to comment.