CORRECTED-UPDATE 2-Japan rebuffs Seoul's calls to scrap export curbs

(Corrects quote in paragraph 14 to "7-8 months". The story was subsequently updated without the quote.)

* Japan could widen curbs, minister says

* Moves could hit S.Korea producers

* Seoul dispatched official to Washington

* Move came weeks before Japan election

By Takaya Yamaguchi and Hyunjoo Jin

TOKYO/SEOUL, July 9 (Reuters) - Japan pushed back on Tuesday against calls from South Korea to scrap curbs on some high-tech exports, ratcheting up tension in a decades-old diplomatic dispute that threatens to disrupt the global supply of memory chips and smartphones.

Tokyo said last week it would tighten restrictions on exports of three materials used in smartphone displays and chips, citing a dispute with Seoul over South Koreans forced to work for Japanese firms during World War Two.

The moves, which could hit tech giants Samsung Electronics and SK Hynix, among others, spotlight Japan's sway over a vital part of the global supply chain that the government is now using as a bargaining chip.

"Whether Japan implements additional measures depends on South Korea's response," Industry Minister Hiroshige Seko told a news conference after a cabinet meeting.

Tokyo was "not thinking at all" of withdrawing the curbs and they did not violate World Trade Organization rules, he added.

In Seoul, a government official said a South Korean foreign ministry official was expected to discuss the curbs with his counterpart in Washington. Its trade minister was also considering travelling to the United States, a spokeswoman said.

Seko's comments were an apparent response to South Korean President Moon Jae-in, who urged on Monday that the restrictions be withdrawn. Seoul could not rule out countermeasures for damage inflicted on its firms, Moon added.

South Korea plans to complain to the WTO.

The row shows no signs of abating, with Tokyo threatening last week to drop Seoul from a "white list" of countries with minimum trade restrictions, hitting supply of a wider range of items used in weapons production.

POTENTIAL TALKS

Tokyo's halt to preferential treatment of the three materials would force exporters to seek permission for each individual shipment to South Korea, taking around 90 days.

The dispute stems from Tokyo's frustration at what it calls a lack of action by Seoul over a South Korean court ruling last October that ordered Nippon Steel to compensate former forced labourers.

Japan says the issue of forced labour was fully settled in 1965 when the neighbours restored diplomatic ties.

The curbs came just weeks before a July 21 upper house election, where Prime Minister Shinzo Abe's Liberal Democratic Party (LDP) and its junior partner are expected to win a solid majority.