The government plans to conduct on-the-spot investigations of South Korean and Taiwanese companies that are exporting polyester staple fiber to Japan at low prices, government officials said Monday.

The investigations are scheduled to begin by the end of the year.

A probe begun in April has so far found insufficient evidence for Japan to decide on antidumping charges against the six Korean and eight Taiwanese firms. However, the Ministry of Economy, Trade and Industry aims to make a decision by next April, officials said.

The plan was unveiled in a meeting of the Industrial Structure Council, an advisory panel to the economy, trade and industry minister.

On April 23, Japan launched an antidumping investigation to decide within a year whether to charge antidumping duties on imports from the companies, which make fiber used to stuff sleeping pads, quilts and cushions.

Documents submitted by September by 229 companies, including domestic producers as well as the exporting manufacturers, allowed for the government to calculate dumping margins for some of the exporters.

The government will also carry out on-the-spot probes domestically to determine the market situation and whether the low-priced imports are causing damage to the domestic industry, they said.

Under World Trade Organization rules, countries are allowed to impose antidumping duties if they find that export prices are set unfairly lower than domestic prices and cause damage to domestic industries.

In light of rising imports of cheap products, five major Japanese textile makers, including Toray Industries Inc., and Teijin Ltd., asked the government on Feb. 28 to impose antidumping duties.

The makers claimed the average dumping margin of the South Korean companies was at 32.5 percent and companies from Taiwan at 8.8 percent.

Japan has imposed antidumping duties on imports twice in the past. The last time was in 1995 on cotton yarn imports from Pakistan, whose companies were charged higher duties of between 2.1 percent and 7.9 percent from August 1995 to August 2000.