Toshiba Corp. warned Tuesday that its group net loss for the first half is likely to widen to 25 billion yen due to weak personal computer sales.

The company initially forecast a 15 billion yen net loss for the six months through September.

The world's No. 3 laptop computer maker is forecasting that its PC and peripherals business will log an operating loss of 17 billion yen for the first half, from a 5.5 billion yen operating profit a year ago.

It blamed sharp price falls in the U.S. PC market triggered by Hewlett-Packard and Dell.

Toshiba, once a dominant leader in the laptop market but now trailing Hewlett-Packard and Dell, said it plans to cut losses in the second half by restructuring its PC product development and marketing.

The company said it will reduce the number of platforms used for its laptops by 30 percent and cut the number of parts by 20 percent. It will increase outsourcing production of Toshiba-brand PCs to concentrate its resources on higher-end models.

"The biggest factor in the PC business slump is that we have expanded the number of platforms way too much," Toshiba President Tadashi Okamura said. "As the result, resources for product development, production and marketing have thinned out."

The company said it will shift its customer focus from large corporations to small and midsize businesses and individual users so it can respond better to the growing demand in the latter market.

As the result reorganizing its sales forces, it will slash about 500 workers in its domestic and overseas offices.