Toshiba is offering to replace a further 830,000 laptop batteries containing cells made by Sony. The offer covers computers sold worldwide and is separate from a similar announcement made by the company last week.

Toshiba is offering to exchange the batteries to ease customer concerns in the light of several recent high-profile battery recalls, it said.

"There is no safety issue, we will voluntarily exchange the battery pack used in certain notebooks," said Keisuke Ohmori, a spokesman for Toshiba in Tokyo.

The announcement came less than a day after Lenovo Group said it would replace batteries for 526,000 of its laptops sold in 2005 and 2006.

Last week, Toshiba offered to exchange 340,000 notebook batteries because it said they could unexpectedly cut power, causing users to lose unsaved work.

The latest offer covers batteries in the following laptop models: Satellite T10, T11, T12, T20, A50; Tecra M3, M4, M5, M7, S3; Portege S100, M300, M400, M500; Dynabook SS LX, L10, L11, M10, M11, M35, MX, MXW; Dynabook R10; Dynabook TX/2, TX/3, TX4; and Qosmio G30 and F30.

Other models sold only overseas are also covered but were not named by Toshiba in Japan.