Sojitz said that year-to-date shipments were already near this level.

The export squeeze resulted in price hikes of around 20% in international trade last month. The metals are used in hybrid cars, laptop computers and missile guidance systems.

Meanwhile, users have been seeking alternative supplies. Sojitz announced a major tie-up with an Australian miner, Lynas Corporation, to secure supplies for the next decade, but the deal is not expected to produce ore until 2012.

Japan and Vietnam have signed a deal to co-operate on rare earths and Mongolian president, Tsakhia Elbegdorj, has called on Japanese companies to invest in rare earths in his country.

Some light was thrown on China’s attitude to rare earth exports at the Hamburg Summit: China meets Europe, held at the Hamburg Chamber of Commerce 25 – 26 November.

The secretary general of China’s State Council, Ma Kai, told the meeting that “the problem of rare earth supply should be addressed through global co-operation”. There was no shortage of supply, he said, but structural problems existed. It was rational and necessary for China to strengthen regulation on rare earth exploitation, production and export, to protect the environment and achieve sustainable development. China abided by WTO rules, he added, when it tightened controls on domestic rare earth product manufacturing.