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.