Tokyo: Japan's trade minister asked industry to limit electricity use at peak periods and ordered nuclear utilities to make strict safety checks, after a strong quake forced the world's biggest nuclear power plant to shut.

Economy, Trade and Industry Minister Akira Amari said yesterday Tokyo Electric Power Co. (TEPCO), the operator of the closed plant, had told him there would be enough power if summer temperatures were average, but there may be shortages if it got too hot.

"Since we can't rule out an unusual rise in demand due to a big jump in temperatures, it is necessary to be on the safe side," Amari told reporters. "We need to ask industry to limit power use during peak periods."

TEPCO's 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.

Lax rules

Fears about the safety of the nuclear industry which supplies about one-third of Japan's electricity have been renewed by the leaks and one expert said planned, tightened rules were still too lax.

TEPCO supplies power to the greater Tokyo area, where peak demand of 68 million kilowatts is forecast during the capital's humid summer.

The firm has asked six utilities to help replace lost production and said power supplies were sufficient for now. Shutting the quake-hit plant deprives TEPCO of up to 8.2 million kilowatts of capacity - around 12 percent of Tokyo's forecast peak demand - which means more power must come from coal- or oil-fired thermal plants and it may need to restart some mothballed plants.

Summer has so far been reasonably cool in Japan, and the meteorological agency said yesterday it expected average or below-average temperatures in late July and early August.