China is likely to purchase billions of yuan of rare-earth minerals starting next month to bolster its strategic reserves, industry sources said.

Du Shuaibing, an analyst with market trends firm Baichuan Information, said that six large rare-earth producers are on the list for the purchasing program, which was launched last year.

This round of purchases will target medium and heavy rare earths, which are more valuable but less common than light rare earths, he added.

Du said it is likely that the plan involves about 10,000 metric tons of rare earths .

The six companies are Baotou Steel Rare Earth Hi-Tech Co, China's largest rare earth producer by output; China Minmetal Rare Earth Co Ltd; China Nonferrous Metal Industry's Foreign Engineering and Construction Co Ltd; Chinalco Rare Earth Jiangsu Co Ltd; Rising Nonferrous Metals Co Ltd and Ganzhou Rare Earth Mineral Industry Co Ltd.

Purchase prices are expected to be slightly above market levels, as was the case last year, he said. If prices were below market levels, he said, "the purchase might not be successful."

But Du added that nothing is confirmed at this stage.

The expected move is aimed at balancing market supplies of rare earths amid a decline in prices and demand this year and leading to expectations of higher prices, Du added.

Despite a brief uptick in August when the nation's rare-earth industry convened at the Fifth China Baotou Rare Earth Industry Forum in Baotou, Inner Mongolia autonomous region, prices of the metals had been declining amid lethargic demand and strong supplies.

Du said that prices will remain depressed in the fourth quarter.

The rare-earth stockpile program, a strategy that many countries has used to ensure the sustainable development of high-tech industries, was launched last year.

Prices were raised after the announcement of purchases of light rare earths for the national reserves.

The State Council originally proposed establishing a national strategic reserve in conjunction with commercial inventories.

China's rare-earth reserves account for about 23 percent of the global total, but they have been over-exploited. As the world's largest producer of rare earths, China provides more than 90 percent of global supplies. But international dependence on China's exports of rare earths has been declining.

Chen Zhanheng, deputy secretary-general of the China Rare Earths Industry Association, urged investors and industry players not to react to reports regarding national reserves by pushing up prices in the short term. He said prices won't be affected by the national strategy.

Liu Yinan, vice-chairman of the China Chamber of Commerce of Metals, Minerals and Chemicals Importers and Exporters, said on Sept 13 that the country's light rare-earth reserves are sufficient for at least 100 years.

He proposed that the national strategic stockpile should focus on medium and heavy rare-earth elements.