Japanese imports of rare earths from China rose six-fold in December from November, reflecting a resumption of trade after Beijing's de-facto ban on shipments halted flows of the minerals for two months since late September.

Japanese Ministry of Finance data showed on Monday that Japanese imports of rare earths from China stood at 4,080 tonnes in December, up from 634 tonnes in November when Tokyo's imports of rare earths further shrank and nearly halted due to the ban.

Japan's rare earths imports from China for all of 2010 stood at 23,310 tonnes, accounting for some 82 percent of the total import volumes, or 28,564 tonnes, of the strategic metals used in high-tech electronics, magnets and batteries.

China, which produces 97 percent of the world's rare earth metals, slashed the export quota by 40 percent in 2010 from 2009 levels to about 30,000 tonnes and plans to trim it further this year. It has already announced increased export taxes on rare earths in 2011.

Japanese companies had complained of restrictions on the metals' shipments, vital for making auto parts and high-tech products, by Chinese customs officials following a spat over disputed islands in the East China Sea which led to a de-facto suspension by Beijing on exports since late September to late November.

The volume imported for the whole of 2010 is equal to the amount allowed under China's export license for just the first half of the year, said a Tokyo-based trading firm official, adding that the jump in the volume for December was a mere rebound from the virtual absence of flows during the ban.

Japanese imports of rare earths from China in 2010 were up 49 percent from 2009, when demand for the industrial metals was hit hard by the global economic slump following the collapse of the Lehman Brothers in late 2008, industry officials said.

We can't say flows of the rare earths are back to normal. Companies remain highly wary of China's restrictions and are eyeing to secure as much as they can while the material is available through trade, the trading firm official said.

Japanese imports of rare earths declined visibly in October, falling 43 percent to 1,278 tonnes from September's 2,246 tonnes.

Japan has been stepping up efforts to diversify its sources of supply of the strategic minerals, including an agreement with Mongolia to cooperate on developing rare earths and striking a tie-up with a mining company in Australia.

China accounted for about 85.5 percent of Japan's total rare earths imports in 2009, slightly higher than in 2010.