The number of items featured on the online auction site of Yahoo Japan Corp. has fallen by nearly 50 percent since early March, due to a recent hike in user fees, officials said Tuesday.

Meanwhile, commission-rate cuts by Bidders, a rival auction site, have helped it nearly double its corresponding figure, they said.

Yahoo, the nation's top Internet portal, is planning to raise user fees again on May 15 and may experience a further decline in items for auction, analysts said.

The number of items on the Yahoo site dipped from 4.4 million in early March to 2.3 million on April 26, Yahoo Japan officials said, adding that the figure has been dropping ever since.

Dena Co., which operates Bidders, said the number of items on its site jumped from 165,000 on April 1 to about 310,000 on May 1 after it cut commission fees by 50 percent on April 2.

Beginning April 15, users of Yahoo's auction site were asked to pay 10 yen for each sale item, which apparently drove some of them over to Bidders.

Yahoo Japan President Masahiro Inoue said, however, that the decline is not a big problem, because it is the result of some users cutting down on large-volume sales of the same products.

He added that the reduction was within a predictable range and that it is now easier for users to find the items they really want.

Dena said it aims to have 1 million items up for auction within six months.

Hiroyuki Kaji, a senior analyst at Stock Research Co., an information technology-related research company, said consumers are benefiting from efforts by Bidders to compete in the online auction market, which has thus far been a monopoly.