Tokyo Electric Power Co. did not fully disclose radiation monitoring data after its Fukushima No. 1 nuclear plant was crippled by the March 11 earthquake and tsunami, the government revealed Friday.

Chief Cabinet Secretary Yukio Edano, after being informed by Goshi Hosono, a special adviser to Prime Minister Naoto Kan, told reporters that he instructed Tepco to sort out the data, make it public and make doubly sure no more information-withholding occurs.

Coming a day after he blasted Tepco's flip-flop over the injection of seawater into the plant's reactor 1, Edano said the government "cannot respond to this matter on the premise" that no more undisclosed information will emerge.