(Reuters) - The operator of Japan's stricken Fukushima Daiichi nuclear plant said on Monday a very high radiation reading that had sent workers fleeing the No. 2 reactor was erroneous.

Tokyo Electric Power Co. (TEPCO) vice-president Sakae Muto apologized for Sunday's error, which added to alarm inside and outside Japan over the impact of contamination from the complex which was hit by an earthquake and tsunami on March 11.

Radiation in the water was a still worrying 100,000 times higher than normal, rather than 10 million times higher as originally stated, Muto said.