South Korea is set to challenge the European Union over duties it has imposed on imports of computer memory chips, the World Trade Organization said.

　　WTO officials said on Tuesday South Korea, which claims the duties breach global trade rules, made a formal request for consultations with the EU. Such a move is usually the first step to a full-blown legal dispute at the global trade body.

　　In April, the EU imposed a provisional 33 percent tax on imports of computer memory chips made by Hynix Semiconductor Inc, accusing the South Korean firm of receiving illegal government subsidies. Hynix is the world's third-largest chip maker.

　　However, the EU cleared another South Korean chipmaker, Samsung Electronics Co, of any wrongdoing.

　　WTO members are allowed to take so-called "countervailing measures" if they believe other members are breaking the rules. But they run the risk of seeing their actions challenged before the WTO's dispute settlement tribunal.

　　The EU Commission initially said the provisional duty would be in force for four months. A formal decision on whether to extend the tax for five years is expected on August 25, but 13 of the 15 EU governments are believed to back continuing the duties.

　　European governments are retaliating against restructuring loans and debt-for-equity swaps made by South Korea's state-controlled banks to Hynix. The tariffs affect millions of dollars in chip exports and deal another heavy blow to Hynix.

　　The EU action foreshadowed a similar move by the United States, which in June slapped a 44.71 per-cent import tariffs on chips made by Hynix. South Korean authorities said they planned to file a dispute with the WTO over the US duty.

　　Last year, Infineon Technologies of Germany and Micron Technology of the United States, the world's second-largest chip maker, filed complaints to the EU and the US Department of Commerce, saying unfair subsidies to their South Korean competitors had allowed them to undercut global chip prices.

　　Dynamic random access memory, or DRAM, chips are South Korea's biggest export item.

　　South Korea exported US5.97 billion worth of DRAM chips last year.