Matsushita Electric Industrial Co. (MC) said Tuesday it has begun recalling 6,000 lithium-ion batteries used in Panasonic-brand notebook computers in Japan on concerns they might overheat.

The recall of the batteries for Let's Note CF-W4G notebook PCs only affects Japan, said company spokesman Akira Kadota.

Kadota said the batteries were not made by Sony Corp. (SNE), whose faulty batteries were involved in far larger recalls by Dell Inc. (DELL) and Apple Computer Inc. (AAPL) last month, but he declined to say who made the batteries, citing an agreement with the manufacturer.

Matsushita has started replacing batteries from the initial shipments of its Let's Note CF-W4G notebook PCs produced in April and May 2005 following two reported cases of trouble earlier this year, he said.

Kadota said that the problem stems from the battery cover, which could become loose. The batteries could produce heat and change shape if the battery cover is damaged due to the poor strength of the latch, he said.

The size of this recall is much smaller than last month's battery recalls by Dell and Apple, which cited concerns that the batteries could overheat and catch fire. Dell asked customers to return 4.1 million faulty laptop batteries, while Apple recalled 1.8 million batteries worldwide.

In both those cases, the problematic lithium-ion batteries were made by Sony Energy Devices Corp., a Japan-based subsidiary of Sony Corp.