TOKYO, July 21 (Reuters) - Japan has turned down an offer of help from the U.N. nuclear watchdog for the time being following last week's quake which damaged the world's biggest nuclear power plant, media reported on Saturday.

The Kashiwazaki-Kariwa nuclear plant was closed indefinitely after Monday's 6.8 magnitude quake in northwestern Japan caused radiation leaks. Ten people were killed by the quake and hundreds of houses were flattened.

Mohamed ElBaradei, the head of the International Atomic Energy Agency (IAEA), had offered to send in inspectors, urging Japan to share the lessons to be learned from the incident.

Kyodo news agency reported sources as saying Japanese nuclear safety authorities would work by themselves to deal with problems at the plant for the time being, but this left room for possibly seeking an IAEA inspection in the future.

Fears about the safety of the nuclear industry -- which supplies about one-third of Japan's electricity -- have been renewed by the leaks.

Television showed officials from Tokyo Electric Power Co. (TEPCO), the operator of the closed plant, meeting with a local government team at the plant on Saturday.

TEPCO has acknowledged that the tremor was stronger than the plant, whose first reactor came on stream more than 20 years ago, had been designed to withstand.

AlertNet news is provided by