Sony has been hit by battery recalls from a number of firms

The recall followed evidence that, in certain circumstances, the batteries could overheat and catch fire.

Major manufacturers including Dell, Hitachi, Apple, Lenovo and Toshiba were among those who recalled the batteries.

Sony said it had found only one problem in the 350,000 batteries recalled from its own-brand laptops.

However, it added that modifications had been made to the production, design and inspection processes to prevent overheating problems in future.

Profits down

"We would like to take this opportunity to apologise for the worries," said Sony's corporate executive officer Yutaka Nakagawa.

Earlier this month, Sony slashed its profit forecast for 2006, setting aside 51bn yen ($429m; �230m) to deal with the costs of the laptop battery recall.

The electronics giant has cut its pre-tax profit forecast for the year to 31 March 2007 by 53% to 70bn yen

On Tuesday, Toshiba increased its estimate on the number of batteries it needed to recall by 40,000 to 870,000.