'Rare cases'

A Toshiba spokesman declined to estimate the cost of the move, and would not say whether Toshiba was asking Sony to foot the bill.

Toshiba said the batteries would die "only in rare cases".

Last month, Dell recalled four million laptop batteries made by Sony, and Apple recalled 1.8 million, after both said there was an over-heating and fire risk.

Dell said it knew of six instances since December when the batteries overheated or caught fire.

Sony has predicted that the recall of its Dell and Apple batteries will cost it between 20bn and 30bn yen ($172m to $258m; £91m to £137m).