Top executives at Japanese electricity producer Tepco are to quit, after the firm admitted possibly having falsified nuclear safety records.

Tepco admitted last week that there may have been problems with maintenance work at its nuclear power plants between the late 1980s and early 1990s, and launched an internal investigation.

The company denied that procedural lapses caused any serious decline in safety, but nonetheless apologised to those living in the vicinity of the affected plants.

"I deeply regret the incident and cannot apologise enough for it," Tepco president Nobuya Minami told a news conference.

Mr Minami will step down in mid-October, and the firm's chairman, vice-president and two advisers will also leave by the end of September.

Touchy issue

The Tepco affair is likely to touch a raw nerve in Japan, which is increasingly dependent on nuclear power.

The Japanese public is highly nervous about the safety of nuclear plants, especially since a radiation leak at a uranium processing facility in Tokaimura three years ago.

Tepco's Kashiwazaki-Kariwa nuclear reactor, the world's largest, will be shut down along with four other reactors for urgent safety checks.

Consumers are also sceptical about corporate honesty after a string of ethical scandals, the most recent involving mislabelled beef at Japan's largest sausage maker, Nippon Meat Packers.

Tepco shares ended down 2%, after losing about 5% since last week when it admitted the investigation.